Applied Physics Letters: All Topics

Cleavage pattern of DNA caused by endonuclease: Theoretical modeling and experimental verification

Shio Inagaki, Li Liu, Masahiro Takinoue, and Kenichi Yoshikawa
In apoptotic cells, genomic DNA molecules are fragmented into multiple fragments with lengths that are integer multiples of approximately 180200 base pairs (bp), i.e., the size of a single nucleosome. Here we propose a simple mathematical model for interpreting this cleavage pattern of DNA. Under th ... [Appl. Phys. Lett. 96, 063701 (2010)] published Tue Feb 9, 2010.

High-Q silica microsphere by poly(methyl methacrylate) coating and modifying

C.-H. Dong, F.-W. Sun, C.-L. Zou, X.-F. Ren, G.-C. Guo et al.
We experimentally characterize the Q-factor in a silica microsphere with the poly(methyl methacrylate) coating. Experimental results demonstrated that the Q-factor of the coated microcavity is higher than 10. Moreover, this coating is able to eliminate scattering from the unsmoothed surface and tune ... [Appl. Phys. Lett. 96, 061106 (2010)] published Tue Feb 9, 2010.

The influence of Ni additions on the relative stability of eta and eta CuSn

U. Schwingenschlogl, C. Di Paola, K. Nogita, and C. M. Gourlay
We investigate how 5 at. % Ni influences the relative stability of eta and eta CuSn. Synchrotron x-ray diffraction shows that, while CuSn exists as eta at 25 and 150 degrees C and transforms to eta on heating to 200 degrees C, CuNiSn is best fit to eta throughout 25200 degrees C. Our first princi ... [Appl. Phys. Lett. 96, 061908 (2010)] published Tue Feb 9, 2010.

High current diffuse dielectric barrier discharge in atmospheric pressure air for the deposition of thin silica-like films

S. A. Starostin, P. Antony Premkumar, M. Creatore, H. de Vries, R. M. J. Paffen et al.
The diffuse dielectric barrier discharge in atmospheric pressure air was applied for the thin film deposition on polymeric web in industrially relevant roll-to-roll configuration. The silica-like film deposition was performed using the admixture of hexamethyldisiloxane precursor to air flow. Fast di ... [Appl. Phys. Lett. 96, 061502 (2010)] published Tue Feb 9, 2010.

Structural defects in LiCoO studied by Li nuclear magnetic relaxation

J. S. Kim, K. W. Lee, J. J. Kweon, Cheol Eui Lee, K. Kim et al.
Microscopic environments and dynamics in LiCoO systems were probed by Li nuclear magnetic relaxation measurements with regard to the structural defects as revealed by x-ray diffraction and electron spin resonance measurements. Thus, the structural defects of differing degrees, associated with Li vac ... [Appl. Phys. Lett. 96, 062504 (2010)] published Tue Feb 9, 2010.

High effective minority carrier lifetime on silicon substrates using quinhydrone-methanol passivation

Bhumika Chhabra, Stuart Bowden, Robert L. Opila, and Christiana B. Honsberg
Iodine-methanol (I/ME), a chemical passivation method, is extensively used in silicon (Si) solar cell fabrication for measuring minority carrier lifetime in bulk regions. We demonstrate that quinhydrone-methanol (QHY/ME) provides higher lifetimes than I/ME. For 0.01 mol/dm QHY/ME on float-zone (FZ) ... [Appl. Phys. Lett. 96, 063502 (2010)] published Tue Feb 9, 2010.

Optical band-gap determination of nanostructured WO film

P. P. Gonzalez-Borrero, F. Sato, A. N. Medina, M. L. Baesso, A. C. Bento et al.
The optical band-gap energy of a nanostructured tungsten trioxide film is determined using the photoacoustic spectroscopy method under continuous light excitation. The mechanism of the photoacoustic signal generation is discussed. The band-gap energy is also computed by other methods. The absorption ... [Appl. Phys. Lett. 96, 061909 (2010)] published Tue Feb 9, 2010.

Anisotropic transport in graphene on SiC substrate with periodic nanofacets

S. Odaka, H. Miyazaki, S.-L. Li, A. Kanda, K. Morita et al.
Anisotropic transport in graphene field-effect transistors fabricated on a vicinal SiC substrate with a self-organized periodic nanofacet structure is investigated. Graphene thermally grown on a vicinal substrate contains two following regions: atomically flat terraces and nanofacets (atomically ste ... [Appl. Phys. Lett. 96, 062111 (2010)] published Tue Feb 9, 2010.

Photoconductivity in single AlN nanowires by subband gap excitation

H. M. Huang, R. S. Chen, H. Y. Chen, T. W. Liu, C. C. Kuo et al.
Photoconductivity of individual aluminum nitride (AlN) nanowires has been characterized using different subband gap excitation sources. It is interesting that both positive (under 1.53 and 2.33 eV excitations) and negative (under 3.06 and 3.81 eV excitations) photocurrent responses are observed from ... [Appl. Phys. Lett. 96, 062104 (2010)] published Tue Feb 9, 2010.

Effect of Mg doping on enhancement of terahertz emission from InN with different lattice polarities

X. Q. Wang, G. Z. Zhao, Q. Zhang, Y. Ishitani, A. Yoshikawa et al.
Effect of Mg doping on terahertz (THz) emission from InN with different lattice polarities was studied. Strong enhancement of THz emission was observed from InN with appropriate Mg-concentrations (10 cm), which is independent of lattice polarity. The buried p-type layers show stronger THz emission ... [Appl. Phys. Lett. 96, 061907 (2010)] published Tue Feb 9, 2010.

Low-temperature solid phase epitaxy for integrating advanced source/drain metal-oxide-semiconductor structures

A. Gouye, I. Berbezier, L. Favre, G. Amiard, M. Aouassa et al.
We show that chemical vapor deposition using trisilane decomposition opens capabilities for the deposition of amorphous silicon on Si substrate at low temperature. Based on this behavior we developed a process including amorphous silicon deposition and crystallization. Transmission electron microsco ... [Appl. Phys. Lett. 96, 063102 (2010)] published Tue Feb 9, 2010.

TaO polymorphs: Structural motifs and dielectric constant from first principles

Wanda Andreoni and Carlo A. Pignedoli
Using large-scale simulations based on density-functional theory we determine the structural properties of several polymorphs of tantalia, their vibrational spectra and dielectric properties. Our calculations indicate that structurally distinct configurations can coexist, having coordination polyhed ... [Appl. Phys. Lett. 96, 062901 (2010)] published Tue Feb 9, 2010.

Terahertz conductivity of doped silicon calculated using the ensemble Monte Carlo/finite-difference time-domain simulation technique

K. J. Willis, S. C. Hagness, and I. Knezevic
We present terahertz-frequency characterization of doped silicon via a multiphysics numerical technique that couples ensemble Monte Carlo (EMC) simulation of carrier transport and a finite-difference time-domain (FDTD) solver of Maxwell's curl equations. We elucidate the importance of rigorous enfor ... [Appl. Phys. Lett. 96, 062106 (2010)] published Tue Feb 9, 2010.

Effects of additional Ce doping on the luminescence of LiSrSiO:Eu yellow phosphor

Tae-Gon Kim, Hyo-Sug Lee, Chun Che Lin, Taehyung Kim, Ru-Shi Liu et al.
Additional Ce doping improves the luminescence of LiSrSiO:Eu, a yellow phosphor for ultraviolet or blue light-emitting diodes. By examining the photoluminescence of LiSrSiO:Eu, LiSrSiO:Ce, and LiSrSiO:Ce,Eu, it was confirmed that the energy transfer from Ce to Eu ions contributes little to the enhan ... [Appl. Phys. Lett. 96, 061904 (2010)] published Tue Feb 9, 2010.

First-principles investigations of the dielectric properties of crystalline and amorphous SiN thin films

T. Anh Pham, Tianshu Li, Sadasivan Shankar, Francois Gygi, and Giulia Galli
We have investigated the dielectric properties of silicon nitride thin films with thickness below 6 nm, by using density functional theory calculations. We find a substantial decrease in the static dielectric constant of crystalline films, as their size is reduced. The variation in the response in p ... [Appl. Phys. Lett. 96, 062902 (2010)] published Tue Feb 9, 2010.

Highly tensile-strained, type-II, GaInAs/GaSb quantum wells

T. Taliercio, A. Gassenq, E. Luna, A. Trampert, and E. Tournie
We have investigated the properties of highly tensile-strained (Ga,In)As layers in a GaSb matrix. In situ observations of the growth mode suggest the formation of (Ga,In)As quantum dots. In contrast, ex situ transmission electron microscopy evidences the formation of perfect quantum wells with the p ... [Appl. Phys. Lett. 96, 062109 (2010)] published Tue Feb 9, 2010.

Single-walled carbon-nanotube-deposited tapered fiber for four-wave mixing based wavelength conversion

K. K. Chow, M. Tsuji, and S. Yamashita
We report the observation of four-wave mixing (FWM) in single-walled carbon nanotubes (CNTs) deposited around a tapered fiber. The third-order nonlinearity of CNTs is originated from the interband transitions of the pi-electrons causing nonlinear polarization similar to other highly-nonlinear organi ... [Appl. Phys. Lett. 96, 061104 (2010)] published Tue Feb 9, 2010.

Optical and electro-optic anisotropy of epitaxial BaSrTiO thin films

D. Y. Wang, S. Li, H. L. W. Chan, and C. L. Choy
The anisotropic optical and electro-optic properties of ferroelectric BaSrTiO thin films, deposited on highly transparent single-crystal MgO (001), (011), and (111) substrates using pulsed laser deposition, were investigated. The experimental results show a strong correlation between optical, electr ... [Appl. Phys. Lett. 96, 061905 (2010)] published Tue Feb 9, 2010.

Reactive radical facilitated reaction-diffusion modeling for holographic photopolymerization

Jianhua Liu, Haihui Pu, Bin Gao, Hongyue Gao, Dejin Yin et al.
A phenomenological concentration of reactive radical is proposed to take the role of curing light intensity in explicit proportion to the reaction rate for the conventional reaction-diffusion model. This revision rationally eliminates the theoretical defect of null reaction rate in modeling of the p ... [Appl. Phys. Lett. 96, 061103 (2010)] published Tue Feb 9, 2010.

Electrically tunable electron g factors in coupled InAs/GaAs pyramid quantum dots

Jiqing Wang, Huibing Mao, Jianguo Yu, Qiang Zhao, Hongying Zhang et al.
The electron g factors of coupled InAs/GaAs quantum dots under external magnetic and electric fields are investigated by using the eight-band kp model. The resonant coupling between the two dots remains under electric fields below 8.2 mV/nm, and is broken above the critical field due to the quantum ... [Appl. Phys. Lett. 96, 062108 (2010)] published Tue Feb 9, 2010.

Strain effects on basal-plane hydrogenation of graphene: A first-principles study

Kun Xue and Zhiping Xu
In this letter we discuss basal-plane hydrogenation of graphene, in the extent of intercoupling between strain and electronic structure. Our first-principles calculations reveal that the atomic structures, binding energies, mechanical and electronic properties of graphene are significantly modified ... [Appl. Phys. Lett. 96, 063103 (2010)] published Tue Feb 9, 2010.

Modeling of leakage currents in high-kappa dielectrics: Three-dimensional approach via kinetic Monte Carlo

Gunther Jegert, Alfred Kersch, Wenke Weinreich, Uwe Schroder, and Paolo Lugli
We report on a simulation algorithm, based on kinetic Monte Carlo techniques, that allows us to investigate transport through high-permittivity dielectrics. In the example of TiN/ZrO/TiN capacitor structures, using best-estimate physical parameters, we have identified the dominant transport mechanis ... [Appl. Phys. Lett. 96, 062113 (2010)] published Tue Feb 9, 2010.

On the origin of leakage current reduction in TiO passivated porosus silicon Schottky-barrier diode

J. D. Hwang and C. H. Chou
Significant reduction by 40 times was achieved in the leakage current of TiO passivated porous silicon (PS) Schottky-barrier diode, compared to that of as-grown PS one. It was found that the imperfect native oxide, nonstoichiometric Si-suboxide (SiO) and Si-O bond with nonbridging oxygen, and highly ... [Appl. Phys. Lett. 96, 063503 (2010)] published Tue Feb 9, 2010.

Measurement of the hot electron attenuation length of copper

J. J. Garramone, J. R. Abel, I. L. Sitnitsky, L. Zhao, I. Appelbaum et al.
Ballistic electron emission microscopy is utilized to investigate the hot-electron scattering properties of Cu through Cu/Si(001) Schottky diodes. A Schottky barrier height of 0.640.02 eV and a hot-electron attenuation length of 33.42.9 nm are measured at a tip bias of 1.0 eV and a temperature of ... [Appl. Phys. Lett. 96, 062105 (2010)] published Tue Feb 9, 2010.

Determination of the microstructure of Eu-treated ZnO nanowires by x-ray absorption

W. L. Huang, J. Labis, S. C. Ray, Y. R. Liang, C. W. Pao et al.
X-ray absorption near-edge structure (XANES), extended x-ray absorption fine structures (EXAFS), and photoluminescence measurements were used to elucidate the microstructural and photoluminescence properties of ZnO nanowires (ZnO-NWs) that had been treated with Eu by thermal diffusion. The O K- and ... [Appl. Phys. Lett. 96, 062112 (2010)] published Tue Feb 9, 2010.

Soliton self-deflection via power-dependent walk-off

Armando Piccardi, Alessandro Alberucci, and Gaetano Assanto
We demonstrate, both experimentally and theoretically, excitation-dependent self-bending of spatial solitons in nematic liquid crystals. The observed deflection is explained by nonlinear changes in walk-off, as induced by the rotation of the optic axis via power-driven reorientation. ... [Appl. Phys. Lett. 96, 061105 (2010)] published Tue Feb 9, 2010.

Observation of shallow-donor muonium in GaO: Evidence for hydrogen-induced conductivity

P. D. C. King, I. McKenzie, and T. D. Veal
The electrical nature of muonium in the transparent conducting oxide material GaO is investigated via muon-spin rotation and relaxation spectroscopy. It is found to be a shallow donor, with an effective donor depth of 15<=E<=30 meV and a hyperfine splitting of 0.130.01 MHz. This is in contrast to ... [Appl. Phys. Lett. 96, 062110 (2010)] published Tue Feb 9, 2010.

Interband cascade photovoltaic devices

Rui Q. Yang, Zhaobing Tian, J. F. Klem, Tetsuya D. Mishima, Michael B. Santos et al.
A photovoltaic (PV) device based on an interband cascade (IC) structure is proposed for efficiently converting solar and thermal energy to electricity. These IC PV devices employ absorption and transport regions with characteristics that are favorable for achieving high open-circuit voltage and thus ... [Appl. Phys. Lett. 96, 063504 (2010)] published Tue Feb 9, 2010.

Identification of extremely radiative nature of AlN by time-resolved photoluminescence

T. Onuma, K. Hazu, A. Uedono, T. Sota, and S. F. Chichibu
Extremely radiative nature of high-quality AlN single crystalline epilayers was identified by means of far ultraviolet time-resolved photoluminescence using a frequency-quadrupled femtosecond AlO:Ti laser. The gross radiative lifetimes of a free excitonic polariton emission as short as 10 ps at 7 K ... [Appl. Phys. Lett. 96, 061906 (2010)] published Tue Feb 9, 2010.

A microprobe technique for simultaneously measuring thermal conductivity and Seebeck coefficient of thin films

Yanliang Zhang, Claudiu L. Hapenciuc, Eduardo E. Castillo, Theodorian Borca-Tasciuc, Rutvik J. Mehta et al.
We demonstrate a microprobe technique that can simultaneously measure thermal conductivity kappa and Seebeck coefficient alpha of thin films. In this technique, an alternative current joule-heated V-shaped microwire that serves as heater, thermometer and voltage electrode, locally heats the thin fil ... [Appl. Phys. Lett. 96, 062107 (2010)] published Tue Feb 9, 2010.

Efficiency droop in 245247 nm AlGaN light-emitting diodes with continuous wave 2 mW output power

W. Sun, M. Shatalov, J. Deng, X. Hu, J. Yang et al.
We report on 245247 nm AlGaN-based deep ultraviolet (DUV) light-emitting diodes with continuous wave output power up to 2 mW. DUV diodes with peak emission wavelength of 245 and 247 nm exhibit turn-on voltage less than 10 V. At room temperature and cw operation the maximum external quantum efficienc ... [Appl. Phys. Lett. 96, 061102 (2010)] published Tue Feb 9, 2010.

Breakdown probability of neon under the influence of field electron emission and surface charges on the cathode surface

V. Lj. Markovic, S. R. Gocic, and S. N. Stamenkovic
Improved relations are suggested to determine of the breakdown probability in neon under the influence of field electron emission and surface charges on the gold plated cathode surfaces. The influence of field electron emission from a vacuum deposited gold layer is confirmed by the FowlerNordheim pl ... [Appl. Phys. Lett. 96, 061501 (2010)] published Mon Feb 8, 2010.

Ultrafast terahertz photoconductivity in nanocrystalline mesoporous TiO films

H. Nemec, P. Kuzel, F. Kadlec, D. Fattakhova-Rohlfing, J. Szeifert et al.
Terahertz time-resolved spectroscopy is used to investigate the transport of photoexcited electrons in nanocrystalline mesoporous TiO films prepared by the recently proposed brick and mortar technology [Szeifert et al.Chem. Mater. 21, 1260 (2009)] with a variable fraction of nanocrystalline titania ... [Appl. Phys. Lett. 96, 062103 (2010)] published Mon Feb 8, 2010.

Temperature-dependent shear band dynamics in a Zr-based bulk metallic glass

David Klaumunzer, Robert Maass, Florian H. Dalla Torre, and Jorg F. Loffler
Flow serrations recorded during inhomogeneous deformation of ZrTiCuNiAl (Vit105) were studied during compression testing at temperatures between 40 and 60 degrees C. The shear band velocities determined exhibit a pronounced temperature dependence covering nearly two orders of magnitude. The velocit ... [Appl. Phys. Lett. 96, 061901 (2010)] published Mon Feb 8, 2010.

Statistical composition-structure-property correlation and glass-forming ability based on the full icosahedra in CuZr metallic glasses

Z. D. Sha, Y. P. Feng, and Y. Li
Using the large-scale atomic/molecular massively parallel simulator, fraction of the Cu-centered <0,0,12,0> full icosahedra (f) is obtained from a statistical analysis over a broad compositional range with high resolution in the CuZr binary system. Weak but significant peaks are observed at certain ... [Appl. Phys. Lett. 96, 061903 (2010)] published Mon Feb 8, 2010.

Losses in coplanar waveguide resonators at millikelvin temperatures

P. Macha, S. H. W. van der Ploeg, G. Oelsner, E. Il'ichev, H.-G. Meyer et al.
We study the loss rate for a set of lambda/2 coplanar waveguide resonators at millikelvin temperatures (20900 mK) and different applied powers (31010 W). The loss rate becomes power independent below a critical power. For a fixed power, the loss rate increases significantly with decreasing temperat ... [Appl. Phys. Lett. 96, 062503 (2010)] published Mon Feb 8, 2010.

Atomic scale analysis of self assembled GaAs/AlGaAs quantum dots grown by droplet epitaxy

J. G. Keizer, J. Bocquel, P. M. Koenraad, T. Mano, T. Noda et al.
In this letter we have performed a structural analysis at the atomic scale of GaAs/AlGaAs quantum dots grown by droplet epitaxy. The shape, composition, and strain of the quantum dots and the AlGaAs matrix are investigated. We show that the GaAs quantum dots have a Gaussian shape and that minor inte ... [Appl. Phys. Lett. 96, 062101 (2010)] published Mon Feb 8, 2010.

Self-assembled templating for the growth of molecular nanodots

Takashi Yokoyama
A checkerboard pattern of alpha-sexithiophene (alpha-6T) with an approximate lattice size of 2.6 x 3.3 nm has been achieved on a Ag(110) surface at monolayer coverage, which is formed through a lateral ordering of two oriented molecules and vacancy defects. We find that this self-assembled pattern ... [Appl. Phys. Lett. 96, 063101 (2010)] published Mon Feb 8, 2010.

Hierarchical nanostructured spherical carbon with hollow core/mesoporous shell as a highly efficient counter electrode in CdSe quantum-dot-sensitized solar cells

Sheng-Qiang Fan, Baizeng Fang, Jung Ho Kim, Jeum-Jong Kim, Jong-Sung Yu et al.
Hierarchical nanostructured spherical carbon with hollow core/mesoporous shell (HCMS) was explored as a counter electrode in CdSe quantum-dot-sensitized solar cells. Compared with conventional Pt electrodes and commercially available activated carbon, the HCMS carbon counter electrode exhibits a muc ... [Appl. Phys. Lett. 96, 063501 (2010)] published Mon Feb 8, 2010.

Crystallitic orientation effects on charge transport in polythiophene thin-film transistors

Liping Zhou, Xue-Feng Wang, Qin Han, Jian-Chun Wu, and Zhen-Ya Li
We simulate charge transport through polymer grain boundaries under the buried critical interface of polymer and dielectric in polythiophene thin-film transistors and find the recently observed enhancement of electronic conduction can be a result of optimized crystallitic orientation. The simulation ... [Appl. Phys. Lett. 96, 063301 (2010)] published Mon Feb 8, 2010.

Suppression of complex domain wall behavior in NiFe nanowires by oscillating magnetic fields

K. Weerts, W. Van Roy, G. Borghs, and L. Lagae
We have studied the field-induced propagation of domain walls (DW) in 750 nm wide magnetic nanowires by time-resolved magneto-optical Kerr microscopy. Two different DW propagation modes are observed, separated by the so-called Walker breakdown (WB), with velocities ranging from 250 till 500 m/s. At ... [Appl. Phys. Lett. 96, 062502 (2010)] published Mon Feb 8, 2010.

Thermoreflectance characterization of band-edge excitonic transitions in CuAlS ultraviolet solar-cell material

Ching-Hwa Ho
Near band edge transitions of CuAlS chalcopyrite crystals have been characterized using temperature-dependent thermoreflectance (TR) spectroscopy in the temperature range between 30 and 340 K. A lot of interband transition features of E, E, E, E, E, E, and E were detected in the low-temperature TR s ... [Appl. Phys. Lett. 96, 061902 (2010)] published Mon Feb 8, 2010.

Perpendicular FePt-based exchange-coupled composite media

D. Makarov, J. Lee, C. Brombacher, C. Schubert, M. Fuger et al.
Exchange-coupled composite media were realized by combining perpendicular hard magnetic FePtCu alloy films with perpendicular Co/Pt multilayers which are magnetically softer. We demonstrate that the switching field of the hard layer can be efficiently altered by modifying the material properties of ... [Appl. Phys. Lett. 96, 062501 (2010)] published Mon Feb 8, 2010.

Mobility analysis of highly conducting thin films: Application to ZnO

D. C. Look, K. D. Leedy, D. H. Tomich, and B. Bayraktaroglu
Hall-effect measurements have been performed on a series of highly conductive thin films of Ga-doped ZnO grown by pulsed laser deposition and annealed in a forming-gas atmosphere (5% H in Ar). The mobility as a function of thickness d is analyzed by a simple formula involving only ionized-impurity a ... [Appl. Phys. Lett. 96, 062102 (2010)] published Mon Feb 8, 2010.

Group velocity dispersion and self phase modulation in silicon nitride waveguides

D. T. H. Tan, K. Ikeda, P. C. Sun, and Y. Fainman
The group velocity dispersion (GVD) of silicon nitride waveguides, prepared using plasma enhanced chemical vapor deposition, is studied and characterized experimentally in support of nonlinear optics applications. We show that the dispersion may be engineered by varying the geometry of the waveguide ... [Appl. Phys. Lett. 96, 061101 (2010)] published Mon Feb 8, 2010.

Reduced photocurrent lag using unipolar solid-state photoconductive detector structures: Application to stabilized n-i-p amorphous selenium

A. H. Goldan, O. Tousignant, L. Laperriere, and K. S. Karim
Memory effects in direct detection solid-state photoconductors are attributed to interrupted charge transport by traps in the bulk and result in persistent photocurrent lag and ghosting. The identified sources for image lag following the cessation of x-ray exposure are the inhomogeneous electric fie ... [Appl. Phys. Lett. 96, 053507 (2010)] published Fri Feb 5, 2010.

Gyrotropic photonic crystal waveguide switches

Z. Wu, Miguel Levy, V. J. Fratello, and A. M. Merzlikin
Functional photonic crystals fabricated in iron garnet films are shown to provide magnetically-controllable optical switching. Transverse-electric and transverse-magnetic stop band separation in conjunction with optical gyrotropy are utilized to selectively block and transmit near-infrared light in ... [Appl. Phys. Lett. 96, 051125 (2010)] published Fri Feb 5, 2010.

Herringbone buckling patterns of anisotropic thin films on elastomeric substrates

J. Song
Highly ordered herringbone buckling patterns have been observed in stiff thin films on elastomeric substrates under an equibiaxial compression. Existing mechanics models assume the thin film to be isotropic, which does not agree with recent experiments of single crystal thin films (e.g., silicon) on ... [Appl. Phys. Lett. 96, 051913 (2010)] published Fri Feb 5, 2010.

High-efficiency, large-bandwidth silicon-on-insulator grating coupler based on a fully-etched photonic crystal structure

Liu Liu (刘柳), Minhao Pu (蒲敏皓), Kresten Yvind, and Jorn M. Hvam
A grating coupler for interfacing between single-mode fibers and photonic circuits on silicon-on-insulator is demonstrated. It consists of columns of fully etched photonic crystal holes, which are made in the same lithography and etching processes used for making the silicon-on-insulator wire wavegu ... [Appl. Phys. Lett. 96, 051126 (2010)] published Fri Feb 5, 2010.

Structural and compositional dependence of gadolinium-aluminum oxide for the application of charge-trap-type nonvolatile memory devices

Youngmin Park, Jong Kyung Park, Myeong Ho Song, Sung Kyu Lim, Jae Sub Oh et al.
The structural and compositional dependence of gadolinium-aluminum oxide (GdAlO) for application to nonvolatile memory is investigated. An addition of Gd into AlO reduces the leakage current, which improves the erase window. The GdAlO film crystallizes into many different phases after annealing depe ... [Appl. Phys. Lett. 96, 052907 (2010)] published Fri Feb 5, 2010.

Interface induced band gap reduction and electron transfer in semiconducting carbon nanotube

M. Zubaer Hossain
Ab initio study of a carbon nanotube-SiO interface reveals that the energetic preference for the nanotube to bind on particular sites on the O-terminated surface differs substantially from that on the Si-terminated surface. Besides, the chemical reactivity at the interface leads to electron-transfer ... [Appl. Phys. Lett. 96, 053118 (2010)] published Fri Feb 5, 2010.

The absorption spectrum of hydrogenated silicon carbide nanocrystals from ab initio calculations

Marton Voros, Peter Deak, Thomas Frauenheim, and Adam Gali
The electronic structure and absorption spectrum of hydrogenated silicon carbide nanocrystals (SiC NCs) have been determined by first principles calculations. We show that the reconstructed surface can significantly change not just the onset of absorption but the shape of the spectrum at higher ener ... [Appl. Phys. Lett. 96, 051909 (2010)] published Fri Feb 5, 2010.

Low-voltage indium gallium zinc oxide thin film transistors on paper substrates

Wantae Lim, E. A. Douglas, D. P. Norton, S. J. Pearton, F. Ren et al.
We have fabricated bottom-gate amorphous (alpha-) indium-gallium-zinc-oxide (InGaZnO) thin film transistors (TFTs) on both paper and glass substrates at low processing temperature (<=100 degrees C). As a water and solvent barrier layer, cyclotene (BCB 302235 from Dow Chemical) was spin-coated on th ... [Appl. Phys. Lett. 96, 053510 (2010)] published Fri Feb 5, 2010.

Hot electron transport and impact ionization in the narrow energy gap InAsN alloy

O. Makarovsky, W. H. M. Feu, A. Patane, L. Eaves, Q. D. Zhuang et al.
We report an experimental study of hot electron dynamics in the narrow band gap dilute nitride alloy, InAsN, with x up to 0.6%. The sharp increase in the conductivity of n-type InAsN at applied electric fields above 1 kV/cm demonstrates that impact ionization dominates the hot electron dynamics. Thi ... [Appl. Phys. Lett. 96, 052115 (2010)] published Fri Feb 5, 2010.

Negative differential resistance and rectifying behaviors in phenalenyl molecular device with different contact geometries

Zhi-Qiang Fan and Ke-Qiu Chen
The electronic transport properties in phenalenyl molecular device are studied by using nonequilibrium Green's functions in combination with the density-functional theory. The results show that the electronic transport properties are strongly dependent on the contact geometry. The negative different ... [Appl. Phys. Lett. 96, 053509 (2010)] published Fri Feb 5, 2010.

The influence of Fermi level pinning/depinning on the Schottky barrier height and contact resistance in Ge/CoFeB and Ge/MgO/CoFeB structures

Donkoun Lee, Shyam Raghunathan, Robert J. Wilson, Dmitri E. Nikonov, Krishna Saraswat et al.
We demonstrated that an ultrathin MgO layer between CoFeB and Ge modulated the Schottky barrier heights and contact resistances of spin diodes. We confirmed that, surprisingly, an insulating MgO layer significantly decreased the Schottky barrier heights and contact resistances of spin diodes on N+Ge ... [Appl. Phys. Lett. 96, 052514 (2010)] published Fri Feb 5, 2010.

Multiferroic heterostructure fringe field tuning of meander line microstrip ferrite phase shifter

A. L. Geiler, S. M. Gillette, Y. Chen, J. Wang, Z. Chen et al.
Magnetic fringe fields emanating from a multiferroic heterostructure composite of Terfenol-D and lead magnesium niobate-lead titanate were utilized to actively tune a meander line microstrip ferrite phase shifter operating above ferrimagnetic resonance at C-band. Differential phase shifts of 65 degr ... [Appl. Phys. Lett. 96, 053508 (2010)] published Fri Feb 5, 2010.

Spatial distribution of two-dimensional electron gas in a ZnO/MgZnO heterostructure probed with a conducting polymer Schottky contact

M. Nakano, A. Tsukazaki, K. Ueno, R. Y. Gunji, A. Ohtomo et al.
A ZnO/MgZnO heterostructure was characterized at T=2 K through capacitance measurements with using a conducting polymer, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), as a Schottky contact. The Nyquist diagram, which is the trajectory curve of the complex impedance vector, ap ... [Appl. Phys. Lett. 96, 052116 (2010)] published Fri Feb 5, 2010.

Surface changes on AlH during the hydrogen desorption

Shunsuke Kato, Michael Bielmann, Kazutaka Ikeda, Shin-ichi Orimo, Andreas Borgschulte et al.
Surface change of alpha-AlH during the hydrogen desorption was investigated by means of in situ x-ray photoelectron spectroscopy combined with thermal desorption spectroscopy. The surface of AlH covered by an oxide layer significantly changes upon hydrogen desorption and the hydrogen desorption rate ... [Appl. Phys. Lett. 96, 051912 (2010)] published Fri Feb 5, 2010.

Negative differential resistance in GaN nanowire network

M. Dragoman, G. Konstantinidis, A. Cismaru, D. Vasilache, A. Dinescu et al.
Negative differential resistance of gallium nitride nanowire networks deposited on an interdigitated electrode configuration patterned on a silicon dioxide/high resistivity Si substrate is experimentally demonstrated at room temperature. This effect is attributed to tunnelling between crossed galliu ... [Appl. Phys. Lett. 96, 053116 (2010)] published Fri Feb 5, 2010.

Ultrafast nanotube based diffusiophoresis nanomotors

Wei Liu, Rongxiang He, Hongwei Zhu, Hao Hu, Meiya Li et al.
Nanomotors represent a significant step forward in nanotechnology, and prove that nanotubes and other nanostructures several hundred times smaller than the diameter of a human hair can be manipulated and assembled into true devices. In this letter, nanotubes based nanomotors are reported. The nanomo ... [Appl. Phys. Lett. 96, 053114 (2010)] published Fri Feb 5, 2010.

Contactless photoconductivity measurements on (Si) nanowires

A. D. Chepelianskii, F. Chiodi, M. Ferrier, S. Gueron, E. Rouviere et al.
Conducting nanowires possess remarkable physical properties unattainable in bulk materials. However our understanding of their transport properties is limited by the difficulty of connecting them electrically. In this letter we investigate phototransport in both bulk silicon and silicon nanowires us ... [Appl. Phys. Lett. 96, 052118 (2010)] published Fri Feb 5, 2010.

A simple strategy to realize biomimetic surfaces with controlled anisotropic wetting

Dong Wu, Qi-Dai Chen, Jia Yao, Yong-Chao Guan, Jian-Nan Wang et al.
The study of anisotropic wetting has become one of the most important research areas in biomimicry. However, realization of controlled anisotropic surfaces remains challenging. Here we investigated anisotropic wetting on grooves with different linewidth, period, and height fabricated by laser interf ... [Appl. Phys. Lett. 96, 053704 (2010)] published Fri Feb 5, 2010.

A translational nanoactuator based on carbon nanoscrolls on substrates

Xinghua Shi, Yuan Cheng, Nicola M. Pugno, and Huajian Gao
Inspired by recent experimental studies on the fabrication of carbon nanoscrolls (CNSs) on solid substrates, we perform theoretical study and molecular dynamics simulations to investigate the translational rolling/unrolling of a CNS on rigid substrate. We show that a substrate-supported CNS can be c ... [Appl. Phys. Lett. 96, 053115 (2010)] published Fri Feb 5, 2010.

Evidence of substrate induced charge order quenching, insulator metal transition, and colossal magnetoresistance in polycrystalline PrCaMnO thin films

Vasudha Agarwal, R. Prasad, M. P. Singh, P. K. Siwach, Amit Srivastava et al.
We report the magnetoelectrical properties of polycrystalline PrCaMnO thin films (thickness~300 nm) deposited on single crystal LaAlO (LAO) and SrTiO (STO) substrates. The films on LAO show charge ordering (CO) at T[approximate]240 K, with a metamagnetic ground state akin to the cluster glass (CG) ... [Appl. Phys. Lett. 96, 052512 (2010)] published Fri Feb 5, 2010.

Demonstration of an air-slot mode-gap confined photonic crystal slab nanocavity with ultrasmall mode volumes

Jie Gao, James F. McMillan, Ming-Chung Wu, Jiangjun Zheng, Solomon Assefa et al.
We demonstrate experimentally an air-slot mode-gap photonic crystal cavity with quality factor of 10 and modal volume of 0.02 cubic wavelengths, based on the design of an air-slot in a width-modulated line-defect in a photonic crystal slab. The origin of the high Q air-slot cavity mode is the mode-g ... [Appl. Phys. Lett. 96, 051123 (2010)] published Fri Feb 5, 2010.

Calibrating the single-wall carbon nanotube resonance Raman intensity by high resolution transmission electron microscopy for a spectroscopy-based diameter distribution determination

P. B. C. Pesce, P. T. Araujo, P. Nikolaev, S. K. Doorn, K. Hata et al.
We study a single-wall carbon nanotube (SWNT) sample grown by water-assisted chemical vapor deposition with both resonance Raman scattering (RRS) and high resolution transmission electron microscopy. High resolution transmission electron microscopy measurements of 395 SWNTs determined the diameter d ... [Appl. Phys. Lett. 96, 051910 (2010)] published Fri Feb 5, 2010.

Graphene mode-lockers for fiber lasers functioned with evanescent field interaction

Yong-Won Song, Sung-Yeon Jang, Won-Suk Han, and Mi-Kyung Bae
Employing graphene as an intracavity passive power modulating element, we demonstrate the efficient laser pulsation in high pulse-energy regime with evanescent field interaction between the propagating light and graphene layer. Graphene is prepared by the solution based reduction of graphene oxide, ... [Appl. Phys. Lett. 96, 051122 (2010)] published Fri Feb 5, 2010.

Bit patterned media based on block copolymer directed assembly with narrow magnetic switching field distribution

O. Hellwig, J. K. Bosworth, E. Dobisz, D. Kercher, T. Hauet et al.
Electron-beam (E-beam) directed assembly, which combines the long-range phase and placement registration of e-beam lithography with the sharp dot size and spacing uniformity of block copolymer self assembly, is considered highly promising for fabricating templates that meet the tight magnetic specif ... [Appl. Phys. Lett. 96, 052511 (2010)] published Fri Feb 5, 2010.

Selection and transfer of individual plasmon-resonant metal nanoparticles

Yoshito Tanaka and Keiji Sasaki
We present a simple method for selecting a single metal nanoparticle with desired localized surface plasmon (LSP) characteristics from particle ensembles on one surface and then transferring it to another surface. The LSP of individual nanoparticles is characterized using a microspectroscopy system. ... [Appl. Phys. Lett. 96, 053117 (2010)] published Fri Feb 5, 2010.

Mixed conduction and chemical diffusion in a Pb(Zr,Ti)O buried capacitor structure

Niall J. Donnelly and Clive A. Randall
Impedance spectroscopy is performed on a buried capacitor structure composed of a PZT-0.75% Nb ceramic with platinum electrodes. The ionic and electronic conductivities (sigma,sigma) are extracted from the impedance spectra using an equivalent circuit based on the premise of mixed conduction. In the ... [Appl. Phys. Lett. 96, 052906 (2010)] published Fri Feb 5, 2010.

Reduced initial degradation of bulk heterojunction organic solar cells by incorporation of stacked fullerene and lithium fluoride interlayers

Kenji Kawano and Chihaya Adachi
Reduced initial degradation of bulk heterojunction organic solar cells (OSCs) was achieved by inclusion of stacked fullerene (C) and lithium fluoride interlayers. By inserting a 3 nm C layer and a 0.5 nm LiF layer between the photoactive layer and Al cathode in an OSC, the device lifetime calculated ... [Appl. Phys. Lett. 96, 053307 (2010)] published Fri Feb 5, 2010.

Electron cyclotron effective mass in indium nitride

Michel Goiran, Marius Millot, Jean-Marie Poumirol, Iulian Gherasoiu, Wladek Walukiewicz et al.
We report on cyclotron effective mass measurement in indium nitride epilayers grown on c-sapphire, using the thermal damping of Shubnikov-de-Haas oscillations obtained in the temperature range 270 K and under magnetic field up to 60 T. We unravel an isotropic electron cyclotron effective mass equal ... [Appl. Phys. Lett. 96, 052117 (2010)] published Fri Feb 5, 2010.

Designed synthesis of materials for high-sensitivity geomagnetic sensors

L. Ding, J. Teng, X. C. Wang, C. Feng, Y. Jiang et al.
A structure of Ta/MgO/NiFe/MgO/Ta was designed and synthesized, which combines the advantages of both tunnel magnetoresistance materials with high magnetic field sensitivity and anisotropic magnetoresistance materials with high directional sensitivity. The magnetoresistance ratio in the device with ... [Appl. Phys. Lett. 96, 052515 (2010)] published Fri Feb 5, 2010.

Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer

Tae-Young Park, Yong-Seok Choi, Jang-Won Kang, Jae-Ho Jeong, Seong-Ju Park et al.
Ga-doped ZnO (ZnO:Ga) films were grown by metalorganic chemical vapor deposition as transparent conducting layers for GaN light-emitting diodes (LEDs). The forward voltage of LEDs with ZnO:Ga was 3.3 V at 20 mA. The low forward voltage was attributed to the removal of a resistive ZnGaO phase, decrea ... [Appl. Phys. Lett. 96, 051124 (2010)] published Fri Feb 5, 2010.

Fast thermally assisted switching at low current density in (Ga,Mn)As magnetic tunnel junctions

Zhen Li, Liesbet Lagae, Gustaaf Borghs, Robert Mertens, and Willem Van Roy
(Ga,Mn)As based magnetic tunnel junctions have potential advantages compared to metal based junctions. In magnetic memory applications, spin-torque switching is the main approach to write information. In addition to the spin-torque effect, the current through the junction also increases the temperat ... [Appl. Phys. Lett. 96, 052513 (2010)] published Fri Feb 5, 2010.

Transport in organic semiconductors in large electric fields: From thermal activation to field emission

J. H. Worne, J. E. Anthony, and D. Natelson
Understanding charge transport in organic semiconductors in large electric fields is relevant to many applications. We present transport measurements in organic field-effect transistors based on poly(3-hexylthiophene) and 6,13-bis(triisopropyl-silylethynyl) (TIPS) pentacene with short channels, from ... [Appl. Phys. Lett. 96, 053308 (2010)] published Fri Feb 5, 2010.

In situ synchrotron x-ray studies of strain and composition evolution during metal-organic chemical vapor deposition of InGaN

M.-I. Richard, M. J. Highland, T. T. Fister, A. Munkholm, J. Mei et al.
Composition and strain inhomogeneities strongly affect the optoelectronic properties of InGaN but their origin has been unclear. Here we report real-time x-ray reciprocal space mapping that reveals the development of strain and composition distributions during metal-organic chemical vapor deposition ... [Appl. Phys. Lett. 96, 051911 (2010)] published Fri Feb 5, 2010.

Cross-sectional magnetic force microscopy of MnAs/GaAs(001)

B. Rache Salles, M. Marangolo, C. David, and J. C. Girard
We investigate the magnetic domain structure and stray field of MnAs/GaAs(001) thin films by magnetic force microscopy of the growth surface and of cleavage edges. The strong uniaxial magnetic anisotropy of MnAs makes the magnetic properties very similar to those of a rectangular bar magnet with con ... [Appl. Phys. Lett. 96, 052510 (2010)] published Fri Feb 5, 2010.

Facile fabrication and biological application of tin-rich indium tin oxide nanorods

Nitin Kumar, Omkar Parajuli, Man Feng, Jian Xu, and Jong-in Hahm
We demonstrate that one-dimensional indium tin oxide nanorods (ITO NRs) with high tin-incorporation ratio can be readily produced with a very good control over size and morphology using a gas-phase synthetic approach. Our current study presents a straightforward and facile growth route to synthesize ... [Appl. Phys. Lett. 96, 053705 (2010)] published Fri Feb 5, 2010.

Space charge limited electron emission from a Cu surface under ultrashort pulsed laser irradiation

W. Wendelen, D. Autrique, and A. Bogaerts
In this theoretical study, the electron emission from a copper surface under ultrashort pulsed laser irradiation is investigated using a one-dimensional particle in cell model. Thermionic emission as well as multiphoton photoelectron emission were taken into account. The emitted electrons create a n ... [Appl. Phys. Lett. 96, 051121 (2010)] published Fri Feb 5, 2010.

Erratum: Ultrafast imaging of photoelectron packets generated from graphite surface [Appl. Phys. Lett. 95, 181108 (2009)]

Ramani K. Raman, Zhensheng Tao, Tzong-Ru Terry Han, and Chong-Yu Ruan
Abstract not available. [Appl. Phys. Lett. 96, 059901 (2010)] published Thu Feb 4, 2010.

Positron annihilation study in SmFeAsO and SmFeAsOF

Y. P. Hao, X. L. Chen, R. H. Liu, W. Kong, B. Cheng et al.
SmFeAsOF polycrystalline samples were first studied by positron annihilation lifetime spectroscopy and Doppler-broadening spectroscopy, combined with the calculated results of positron lifetime. The experimental results agree well with the calculated positron bulk lifetime in SmFeAsO and SmFeAsF cry ... [Appl. Phys. Lett. 96, 052507 (2010)] published Thu Feb 4, 2010.

Dual wavelength emission from a terahertz quantum cascade laser

Joshua R. Freeman, Julien Madeo, Anthony Brewer, Sukhdeep Dhillon, Owen P. Marshall et al.
We describe a heterogeneous terahertz (THz) quantum cascade laser that is composed of two different active region designs. This device emits simultaneously at around 2.5 and 2.9 THz with certain frequency tunability by applied current. We also investigate the spectral gain in the structure by THz ti ... [Appl. Phys. Lett. 96, 051120 (2010)] published Thu Feb 4, 2010.

Structural and electrical properties of ZnO nanorods and Ti buffer layers

C.-H. Kwak, B.-H. Kim, C.-I. Park, S.-Y. Seo, S.-H. Kim et al.
Vertically-well-aligned ZnO nanorods were synthesized on Ti buffer layers by a metal-organic chemical-vapor deposition process. Structural analyses demonstrated that the ZnO nanorods were well-aligned in the c-axis and ab-plane. Transmission electron microscopy (TEM) showed that the Ti buffer layer ... [Appl. Phys. Lett. 96, 051908 (2010)] published Thu Feb 4, 2010.

Electric field dependence of nonlinearity parameters and third order elastic constants of 0.70Pb(MgNb)O0.30PbTiO single crystal

Xiaozhou Liu, Shujun Zhang, Jun Luo, Thomas R. Shrout, and Wenwu Cao
Through second harmonic measurements, the ultrasonic nonlinearity parameters of [001] and [111] polarized 0.70Pb(MgNb)O0.30PbTiO(PMN0.3PT) single crystals have been measured as a function of bias electric field. It was found that the nonlinearity parameter increases almost linearly with field at low ... [Appl. Phys. Lett. 96, 052905 (2010)] published Thu Feb 4, 2010.

Doping and optimal electron spin polarization in n-ZnMnSe for quantum-dot spin-injection light-emitting diodes

W. Loffler, N. Hopcke, H. Kalt, S. F. Li, M. Grun et al.
Utilizing the diluted magnetic semiconductor ZnMnSe for electron spin alignment near-perfect spin state preparation in semiconductor quantum dots has been demonstrated. We show that the electron spin polarization depends strongly on the electron concentration in ZnMnSe:Cl. Using a model which takes ... [Appl. Phys. Lett. 96, 052113 (2010)] published Thu Feb 4, 2010.

Surface plasmon excitation in silver nanowires directly deposited on a laser diode chip

Zhe Ma, Xining Zhang, Xin Guo, Qing Yang, Yaoguang Ma et al.
We demonstrate surface plasmon (SP) excitation in silver nanowires directly deposited on the emission facet of a laser diode (LD) chip. Evident light output from the silver nanowires is observed. The output is linear-polarized and is strongly dependent on the nanowire orientation. SP excitation at t ... [Appl. Phys. Lett. 96, 051119 (2010)] published Thu Feb 4, 2010.

B diffusion in implanted NiSi and NiSi layers

I. Blum, A. Portavoce, L. Chow, D. Mangelinck, K. Hoummada et al.
B diffusion in implanted NiSi and NiSi layers has been studied using secondary ion mass spectrometry, and compared to B redistribution profiles obtained after the reaction of a Ni layer on a B-implanted Si(001) substrate, in same annealing conditions (400550 degrees C). B diffusion appears faster i ... [Appl. Phys. Lett. 96, 054102 (2010)] published Thu Feb 4, 2010.

Realization of a phononic crystal operating at gigahertz frequencies

M. F. Su, R. H. Olsson, III, Z. C. Leseman, and I. El-Kady
We report on the experimental realization of a phononic crystal, designed to operate at gigahertz frequencies. Detailed studies of the structure have been performed using finite difference time domain method to determine effects of slab modes in finite-thickness slabs, thus enabling precise guidance ... [Appl. Phys. Lett. 96, 053111 (2010)] published Thu Feb 4, 2010.

Observation of an electrically tunable exciton g factor in InGaAs/GaAs quantum dots

F. Klotz, V. Jovanov, J. Kierig, E. C. Clark, D. Rudolph et al.
The electric field dependence of the exciton g factor and the fine structure splitting in self-assembled InGaAs/GaAs quantum dots grown via a flush-overgrowth technique is studied by photocurrent and photoluminescence experiments. Both the fine structure and the Zeeman splitting can be tuned over a ... [Appl. Phys. Lett. 96, 053113 (2010)] published Thu Feb 4, 2010.

Direct investigation on conducting nanofilaments in single-crystalline Ni/NiO core/shell nanodisk arrays

Inrok Hwang, Jinsik Choi, Sahwan Hong, Jin-Soo Kim, Ik-Su Byun et al.
We report resistive switching characteristics of single-crystalline Ni/NiO core/shell nanodisk arrays, in which the conducting filaments are highly localized on the surface of nanostructure. The local current distributions observed in such a single-grained nanodisk demonstrate that the contact area ... [Appl. Phys. Lett. 96, 053112 (2010)] published Thu Feb 4, 2010.

Effect of V/III flux ratio on luminescence properties and defect formation of Er-doped GaN

Shaoqiang Chen, Akira Uedono, Shoji Ishibashi, Shigeo Tomita, Hiroshi Kudo et al.
Erbium-doped GaN samples grown with different V/III ratios through gas source molecular beam epitaxy were prepared to investigate the influence of the V/III ratio on the defect formation and the optical activity of the Er-related luminescence center. Obvious V/III ratio dependence was observed in ph ... [Appl. Phys. Lett. 96, 051907 (2010)] published Thu Feb 4, 2010.

Measurements of the write error rate in bit patterned magnetic recording at 100320 Gb/in

M. Grobis, E. Dobisz, O. Hellwig, M. E. Schabes, G. Zeltzer et al.
We demonstrate a technique for measuring the intrinsic bit-error-rate as a function of write misregistration in bit patterned media. We examine the recording performance at bit densities of 100, 200, and 320 Gigabits per square inch (Gb/in) and find that the on-track write misregistration margin for ... [Appl. Phys. Lett. 96, 052509 (2010)] published Thu Feb 4, 2010.

Emission zone control in blue organic electrophosphorescent devices through chemical modification of host materials

Evgueni Polikarpov, James S. Swensen, Lelia Cosimbescu, Phillip K. Koech, James E. Rainbolt et al.
We report blue organic light-emitting devices with iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C] picolinate as an emitter doped into a series of phosphine oxide-based host materials that have significantly different charge transport properties: 4-(diphenylphosphoryl)-N,N-diphenylaniline (HM ... [Appl. Phys. Lett. 96, 053306 (2010)] published Thu Feb 4, 2010.

Surface-induced magnetism in C-doped SnO

Gul Rahman and Victor M. Garcia-Suarez
The magnetism of C-doped SnO (001) surfaces is studied using first-principles calculations. It is found that carbon does not induce magnetism in bulk SnO when located at the oxygen site but shows a large magnetic moment at the SnO (001) surface. The magnetic moment is mainly contributed by the carbo ... [Appl. Phys. Lett. 96, 052508 (2010)] published Thu Feb 4, 2010.

Giant anisotropic magnetoresistance in insulating ultrathin (Ga,Mn)As

R. R. Gareev, A. Petukhov, M. Schlapps, J. Sadowski, and W. Wegscheider
Molecular-beam epitaxy grown, 5 nm thick annealed GaMnAs films demonstrate transition from metallic to insulating state for sheet resistances near resistance quantum, which we connect with the two-dimensional hole localization. Below the metal-insulator transition we found the giant anisotropic magn ... [Appl. Phys. Lett. 96, 052114 (2010)] published Thu Feb 4, 2010.

Effective work function tuning in high-kappa dielectric metal-oxide-semiconductor stacks by fluorine and lanthanide doping

A. Fet, V. Haublein, A. J. Bauer, H. Ryssel, and L. Frey
In this letter, an ion implantation approach to engineer the effective work function is discussed and an empirical model to explain the mechanisms of work function change is proposed. It is shown that by doping a TiN/HfSiO stack with La and F, a silicon conduction band edge and valence band edge met ... [Appl. Phys. Lett. 96, 053506 (2010)] published Thu Feb 4, 2010.

rf linewidth reduction in a quantum dot passively mode-locked laser subject to external optical feedback

C.-Y. Lin, F. Grillot, N. A. Naderi, Y. Li, and L. F. Lester
The effect of external optical feedback on an InAs/GaAs quantum dot passively mode-locked laser is investigated. The rf linewidth narrows from 8 KHz in the free-running situation to a value as low as 350 Hz under relatively low feedback. The rf linewidth characterization under resonant feedback at a ... [Appl. Phys. Lett. 96, 051118 (2010)] published Thu Feb 4, 2010.

How many surface plasmons are locally excited on the ridges of metallic lamellar gratings?

B. Wang and P. Lalanne
In contrast to earlier classical studies that analyze the surface Bloch modes supported by metallic gratings composed of slits as collective surface-plasmon-polaritons (SPPs) resonances (or poles) of the entire periodic problem, we study the normalized rate of SPPs that are locally launched on every ... [Appl. Phys. Lett. 96, 051115 (2010)] published Wed Feb 3, 2010.

Effect of boron on interstitial-related luminescence centers in silicon

S. Charnvanichborikarn, B. J. Villis, B. C. Johnson, J. Wong-Leung, J. C. McCallum et al.
Photoluminescence measurements have been used to investigate the optically active defect centers formed by silicon implantation and a subsequent anneal at 275, 400, or 525 degrees C. The presence of boron in p-type silicon is found to produce deleterious effects on the luminescence of the interstit ... [Appl. Phys. Lett. 96, 051906 (2010)] published Wed Feb 3, 2010.

Microscopic simulation of nonequilibrium features in quantum-well pumped semiconductor disk lasers

Eckhard Kuhn, Stephan W. Koch, Angela Thranhardt, Jorg Hader, and Jerome V. Moloney
A microscopically motivated nonequilibrium theory is applied to study the power characteristics of an in-well pumped vertical external cavity surface emitting Laser for varying pump energies. Dynamic simulations yield steady state nonequilibrium carrier distributions resulting in gain reduction due ... [Appl. Phys. Lett. 96, 051116 (2010)] published Wed Feb 3, 2010.

Effect of In incorporated into SbTe on phase change characteristics resulting from changes in electronic structure

Moon Hyung Jang, Seung Jong Park, Dong Heok Lim, Sung Jin Park, Mann-Ho Cho et al.
The effects of the In content of InSbTe films with various stoichiometries (SbTe, InSbTe, and InSbTe) on phase change characteristics were investigated. With increasing incorporation of In atoms into SbTe, various crystalline phases, i.e., InTe, Sb, and InSbTe, were observed due to the bond energy b ... [Appl. Phys. Lett. 96, 052112 (2010)] published Wed Feb 3, 2010.

Charge pumping technique to analyze the effect of intrinsically retained charges and extrinsically trapped charges in biomolecules by use of a nanogap embedded biotransistor

Sungho Kim, Jae-Hyuk Ahn, Tae Jung Park, Sang Yup Lee, and Yang-Kyu Choi
Charge pumping technique is investigated for label-free electrical biosensing using a nanogap-embedded biotransistor. Biomolecules immobilized in a nanogap provide additional trap states and charges in the gate dielectric. These two effects give rise to a change of the charge pumping current, which ... [Appl. Phys. Lett. 96, 053702 (2010)] published Wed Feb 3, 2010.

Magnetic noise in MgO-based magnetic tunnel junction rings

J. F. Feng, Z. Diao, Gen Feng, E. R. Nowak, and J. M. D. Coey
Magnetization switching is investigated in ring-shaped MgO-based magnetic tunnel junctions with 168% tunneling magnetoresistance. Besides the forward and reverse onion states, two vortex states and several metastable states are observed for the ferromagnetic free layer. Electrical noise is used to c ... [Appl. Phys. Lett. 96, 052504 (2010)] published Wed Feb 3, 2010.

Tadpole shaped GeMn magnetic semiconductors grown on Si

Yong Wang, Faxian Xiu, Jin Zou, Kang L. Wang, and Ajey P. Jacob
Magnetic and structural properties of a GeMn thin film grown on Si has been investigated by transmission electron microscopy and superconducting quantum interference device. Tadpole shaped coherent GeMn clusters induced by spinodal decomposition were revealed in the film. Although these coherent clu ... [Appl. Phys. Lett. 96, 051905 (2010)] published Wed Feb 3, 2010.

Density functional calculations of hole induced long ranged ferromagnetic ordering in Mn doped CdSe nanocluster

S. Ghosh, B. Sanyal, and G. P. Das
We have investigated the possibility of long ranged ferromagnetic ordering in Mn doped CdSe nanocluster using density functional approach. Following the band repulsion theory we have explained that magnetic coupling between Mn atoms substituted in Cd sites is antiferromagnetic and short ranged. Howe ... [Appl. Phys. Lett. 96, 052506 (2010)] published Wed Feb 3, 2010.

Quantitative phase imaging with broadband fields

Zhuo Wang and Gabriel Popescu
Recently, Wolf has shown that the phase measurement associated with fields that are not monochromatic, which is relevant for all x-ray structure investigations, must be properly defined via a cross-spectral density function under full spatial coherence conditions; otherwise, the problem is meaningle ... [Appl. Phys. Lett. 96, 051117 (2010)] published Wed Feb 3, 2010.

Evidence of Al induced conducting filament formation in Al/amorphous silicon/Al resistive switching memory device

Jung Won Seo, Seung Jae Baik, Sang Jung Kang, Yun Ho Hong, Ji-Hwan Yang et al.
We demonstrated that an Al/p-type amorphous silicon (p-a-Si)/Al switching device exhibits stable, nonvolatile resistive switching characteristics as well as reliable data retention at 85 degrees C. It is directly observed that the conducting filament is created after electroforming and incorporates ... [Appl. Phys. Lett. 96, 053504 (2010)] published Wed Feb 3, 2010.

Effect of Mg doping in the barrier of InGaN/GaN multiple quantum well on optical power of light-emitting diodes

Sang-Heon Han, Chu-Young Cho, Sang-Jun Lee, Tae-Young Park, Tae-Hun Kim et al.
We report on Mg doping in the barrier layers of InGaN/GaN multiple quantum wells (MQWs) and its effect on the properties of light-emitting diodes (LEDs). Mg doping in the barriers of MQWs enhances photoluminescence intensity, thermal stability, and internal quantum efficiency of LEDs. The light outp ... [Appl. Phys. Lett. 96, 051113 (2010)] published Wed Feb 3, 2010.

Multiple diagnostics in a high-pressure hydrogen microwave plasma torch

J. Torres, J. J. A. M. van der Mullen, A. Gamero, and A. Sola
We present an experimental study of a hydrogen plasma produced by a microwave axial injection torch, launching the plasma in a helium-filled chamber. Three different diagnostic methods have been used to obtain the electron density and temperature as follows: The Stark intersection method of Balmer s ... [Appl. Phys. Lett. 96, 051501 (2010)] published Wed Feb 3, 2010.

Room temperature operation of photonic-crystal distributed-feedback quantum cascade lasers with single longitudinal and lateral mode performance

Quan-Yong Lu, Wan-Hong Guo, Wei Zhang, Li-Jun Wang, Jun-Qi Liu et al.
We demonstrate room temperature operation of photonic-crystal distributed-feedback quantum cascade lasers emitting at 4.7 [mu]m. A rectangular photonic crystal lattice perpendicular to the cleaved facet was defined using holographic lithography. The anticrossing of the index- and Bragg-guided dispe ... [Appl. Phys. Lett. 96, 051112 (2010)] published Wed Feb 3, 2010.

Maximum Li storage in Si nanowires for the high capacity three-dimensional Li-ion battery

Kibum Kang, Hyun-Seung Lee, Dong-Wook Han, Gil-Sung Kim, Donghun Lee et al.
Nanowires can serve as three-dimensional platforms at the nanometer scale for highly efficient chemical energy storage and conversion vehicles, such as fuel cells and secondary batteries. Here we report a coin-type Si nanowire (NW) half-cell Li-ion battery showing the Li capacity of approximately 40 ... [Appl. Phys. Lett. 96, 053110 (2010)] published Wed Feb 3, 2010.

Quantum-level control in a IIIV-based ferromagnetic-semiconductor heterostructure with a GaMnAs quantum well and double barriers

Shinobu Ohya, Iriya Muneta, and Masaaki Tanaka
We investigate the spin-dependent tunneling properties in a three-terminal IIIV-based ferromagnetic-semiconductor heterostructure with a 2.5 nm thick GaMnAs quantum well (QW) and double barriers. We successfully control the quantum levels and modulate the spin-dependent current with varying the volt ... [Appl. Phys. Lett. 96, 052505 (2010)] published Wed Feb 3, 2010.

A contour-mode film bulk acoustic resonator of high quality factor in a liquid environment for biosensing applications

Wencheng Xu, Seokheun Choi, and Junseok Chae
This letter reports an acoustic resonator of high quality factors (Qs) operating in liquid media. The film bulk acoustic resonator (FBAR) is made of a ring-shaped piezoelectric aluminum nitride thin film, and is excited in a contour mode. By having a low motional resistance upon coupling with liquid ... [Appl. Phys. Lett. 96, 053703 (2010)] published Wed Feb 3, 2010.

A microtip self-written on a vertical-cavity surface-emitting laser by photopolymerization

V. Bardinal, B. Reig, T. Camps, E. Daran, J. B. Doucet et al.
We present the integration of a self-aligned microtip on a vertical-cavity surface-emitting laser (VCSEL) by near infrared photopolymerization. This one-step fabrication process is triggered by the laser source itself. It is based on the use of photopolymers sensitive at the lasing wavelength and ca ... [Appl. Phys. Lett. 96, 051114 (2010)] published Wed Feb 3, 2010.

Theory of hot-carrier-induced phenomena in GaN high-electron-mobility transistors

Y. S. Puzyrev, B. R. Tuttle, R. D. Schrimpf, D. M. Fleetwood, and S. T. Pantelides
It has long been known that GaN high-electron-mobility transistors can degrade significantly under hot electron stress. More recently, an increase in the yellow luminescence was observed under similar stress conditions. The two phenomena have been attributed to defects but no specific physical mecha ... [Appl. Phys. Lett. 96, 053505 (2010)] published Wed Feb 3, 2010.

High density conics in a magnetically expanding helicon plasma

C. Charles
A two-dimensional mapping of ion density and plasma potential in a diverging magnetized low pressure (0.4 mTorr) carbon dioxide helicon plasma containing a double layer reveals the presence of high density conics (~7 x 10 cm) along the most diverging magnetic field lines exiting the helicon source ... [Appl. Phys. Lett. 96, 051502 (2010)] published Wed Feb 3, 2010.

Tunable interfacial properties of epitaxial graphene on metal substrates

Min Gao, Yi Pan, Chendong Zhang, Hao Hu, Rong Yang et al.
We report on tuning interfacial properties of epitaxially-grown graphenes with different kinds of metal substrates based on scanning tunneling microscopy experiments and density functional theory calculations. Three kinds of metal substrates, Ni(111), Pt(111), and Ru(0001), show different interactio ... [Appl. Phys. Lett. 96, 053109 (2010)] published Wed Feb 3, 2010.

Ultrafast saturable absorption devices incorporating efficiently electrosprayed carbon nanotubes

Suho Chu, Won-Suk Han, Il-Doo Kim, Young-Geun Han, Kwanil Lee et al.
We demonstrate saturable absorption operation of single-walled carbon nanotubes (CNTs) deposited by an efficient electrospray process that provides target-localized deposition with a homogeneous dispersion of the nanomaterials. An improvement in deposition efficiency of 95% is achieved. CNT dispersi ... [Appl. Phys. Lett. 96, 051111 (2010)] published Wed Feb 3, 2010.

Second-harmonic generation from a single wurtzite GaAs nanoneedle

Roger Chen, Shanna Crankshaw, Thai Tran, Linus C. Chuang, Michael Moewe et al.
We report and characterize second-harmonic generation from a single wurtzite GaAs nanoneedle. The wurtzite crystal structure of the nanoneedle relaxes the strict nonlinear selection rules of normal zincblende GaAs while maintaining its strong nonlinear optical coefficients. The ability to grow GaAs ... [Appl. Phys. Lett. 96, 051110 (2010)] published Tue Feb 2, 2010.

Hydrogen and inert species in solid phase epitaxy

R. R. Lieten, S. Degroote, F. Clemente, M. Leys, and G. Borghs
The incorporation of hydrogen during deposition of amorphous germanium can influence solid phase epitaxy in many ways. We show that GeH bonds are not important during the crystallization process. However, atomic hydrogen is important during deposition to obtain a highly disordered layer. We have fou ... [Appl. Phys. Lett. 96, 052109 (2010)] published Tue Feb 2, 2010.

Monolayer rigid arrays of cavity-controllable metallic mesoparticles: Electrochemical preparation and light transmission resonances

Zhuo Chen, Han Dong, Jian Pan, Peng Zhan, Chaojun Tang et al.
We report an efficient and robust electrochemical deposition method to fabricate large-scale two-dimensional rigid arrays of metal colloids with a precise control of the particle morphology by monitoring metal growth that is confined within a templated organic porous mold. Light transmission resonan ... [Appl. Phys. Lett. 96, 051904 (2010)] published Tue Feb 2, 2010.

Resistance-dependent amplitude of random telegraph-signal noise in resistive switching memories

Daniele Ielmini, Federico Nardi, and Carlo Cagli
Resistive-switching memory (RRAM) is attracting a considerable interest for the development of high-density nonvolatile memories. However, several scaling and reliability issues still affect the development path of RRAM. This work addresses random telegraph-signal noise (RTN) of the RRAM current, po ... [Appl. Phys. Lett. 96, 053503 (2010)] published Tue Feb 2, 2010.

Hydrogen generation by solar water splitting using p-InGaN photoelectrochemical cells

K. Aryal, B. N. Pantha, J. Li, J. Y. Lin, and H. X. Jiang
Photoelectrochemical effects in p-InGaN (0<=x<=0.22) alloys have been investigated. Hydrogen generation was observed in p-InGaN semiconducting electrodes under white light illumination with additional bias. It was found that p-InGaN alloys possess much higher conversion efficiencies than p-GaN. Time ... [Appl. Phys. Lett. 96, 052110 (2010)] published Tue Feb 2, 2010.

Wide-bandgap ZnGeO nanowire networks as efficient ultraviolet photodetectors with fast response and recovery time

Chaoyi Yan, Nandan Singh, and Pooi See Lee
Ultraviolet (UV) photodetectors based on ternary ZnGeO nanowire (NW) networks are demonstrated. The devices show fast response and recovery time, which is attributed to the unique NW-NW junction barrier dominated conductance for network devices. The UV-light induced barrier height modulation is much ... [Appl. Phys. Lett. 96, 053108 (2010)] published Tue Feb 2, 2010.

A study of resistive switching effects on a thin FeO transition layer produced at the oxide/iron interface of TiN/SiO/Fe-contented electrode structures

Li-Wei Feng, Chun-Yen Chang, Yao-Feng Chang, Wei-Ren Chen, Shin-Yuan Wang et al.
Large (>10) and stable resistance switching characteristics were demonstrated in TiN/SiO/Fe structure due to the presence of a thin FeO transition layer at the SiO/Fe interface, produced spontaneously during the plasma-enhanced tetraethyl orthosilicate oxide deposition process. Addition of Pt into F ... [Appl. Phys. Lett. 96, 052111 (2010)] published Tue Feb 2, 2010.

Observation of sub-100 femtosecond electron cooling time in InN

Yi-En Su, Yu-Chieh Wen, Hong-Mao Lee, Shangjr Gwo, and Chi-Kuang Sun
We report that the electron cooling time in indium nitride can be as fast as sub-100 femtosecond at low electron concentration (<5 x 10/cm), which is much faster than previous reports. Through investigating the dependence of the measured carrier cooling time on electron density, our study proved the ... [Appl. Phys. Lett. 96, 052108 (2010)] published Tue Feb 2, 2010.

Highly selective separation of DNA fragments using optically directed transport

Avital Braiman, Fedor Rudakov, and Thomas Thundat
We present a design that allows selective separation of biomolecules of a particular size without performing complete separation of the sample by size. By focusing a laser beam onto a photoelectrode in contact with an electrolyte medium, a highly localized and optically controlled photoelectrophoret ... [Appl. Phys. Lett. 96, 053701 (2010)] published Tue Feb 2, 2010.

Role of carrier and spin in tuning ferromagnetism in Mn and Cr-doped InO thin films

Feng-Xian Jiang, Xiao-Hong Xu, Jun Zhang, Xiao-Chen Fan, Hai-Shun Wu et al.
Mn and Cr-doped InO films with Sn codoping were deposited on sapphire substrate by pulsed laser deposition. The ferromagnetism of Mn-doped InO films shows reversible behavior, which can be switched between on and off states by controlling the carrier density via varying Sn concentration. The enhance ... [Appl. Phys. Lett. 96, 052503 (2010)] published Tue Feb 2, 2010.

Supergrains produced by lateral growth using Joule-heating induced crystallization without artificial control

Won-Eui Hong, Jangkyun Chung, Donghyun Kim, Seungho Park, and Jae-Sang Ro
In Joule-heating induced crystallization, phase transformation can occur through solid-to-solid or liquid-to-solid phases, according to the input conditions of the pulsed power. It was observed that during a Joule-heating period of several tens of microseconds, randomly nucleated liquid seeds follow ... [Appl. Phys. Lett. 96, 052105 (2010)] published Tue Feb 2, 2010.

Study of defect-dipoles in an epitaxial ferroelectric thin film

C. M. Folkman, S. H. Baek, C. T. Nelson, H. W. Jang, T. Tybell et al.
We have analyzed the defect contributions to the in-plane polarization switching of epitaxial (001) BiFeO thin films on (110) TbScO substrates. Interdigitated electrodes were patterned with respect to ferroelectric stripe domains in the BiFeO film. Polarization measurements exhibited a clear double ... [Appl. Phys. Lett. 96, 052903 (2010)] published Tue Feb 2, 2010.

Hollow-core resonator based on out-of-plane two-dimensional photonic band-gap crystal cladding at microwave frequencies

Georges Humbert, Jean-Michel Le Floch, David Mouneyrac, Denis Ferachou, Michel Aubourg et al.
We report on the demonstration of a resonator based on electromagnetic field confinement in a hollow-core by implementing an out-of-plane two-dimensional (2D) photonic band-gap (PBG) crystal cladding. In contrast with in-plane 2D PBG crystal devices, the PBG crystal studied here is perpendicular to ... [Appl. Phys. Lett. 96, 051108 (2010)] published Tue Feb 2, 2010.

Band bending effect induced by gate voltage on the charge loss behavior of charge trap flash memory devices

M. Chang, H. Hwang, and S. Jeon
We found that the polarity of the gate voltage (V) during the retention characteristics for a SiO/SiN/AlO (ONA) stack can affect the charge loss direction, due to band bending. Positive V could induce electron de-trapping through AlO, while a negative V could induce the same through SiO. Consequentl ... [Appl. Phys. Lett. 96, 052106 (2010)] published Tue Feb 2, 2010.

The impact of piezoelectric polarization and nonradiative recombination on the performance of (0001) face GaN/InGaN photovoltaic devices

J. J. Wierer, Jr., A. J. Fischer, and D. D. Koleske
The impact of piezoelectric polarization and nonradiative recombination on the short-circuit current densities (J) of (0001) face GaN/InGaN photovoltaic devices is demonstrated. P-i-n diodes consisting of 170 nm thick intrinsic InGaN layers sandwiched by GaN layers exhibit low J~40 [mu]A/cm. The pi ... [Appl. Phys. Lett. 96, 051107 (2010)] published Tue Feb 2, 2010.

Process temperature dependent high frequency capacitance-voltage response of ZrO/GeO/germanium capacitors

O. Bethge, S. Abermann, C. Henkel, C. J. Straif, H. Hutter et al.
ZrO/GeO dielectrics are grown on germanium substrates by Atomic Layer Deposition (ALD) at substrate temperatures of 150, 200, and 250 degrees C, respectively. The impact of the deposition temperature on the electrical and structural properties of MOS capacitors is investigated. A significant influe ... [Appl. Phys. Lett. 96, 052902 (2010)] published Tue Feb 2, 2010.

Thickness dependent absorption spectra in conjugated polymers: Morphology or interference?

Olivier P. M. Gaudin, Ifor D. W. Samuel, Samia Amriou, and Paul L. Burn
The thickness dependence of the absorption spectrum of spin-coated films of poly[2-(2-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene] has been studied using reflectivity and variable angle spectroscopic ellipsometry measurements. It is found that, for films with thicknesses in the range of 18178 nm, ... [Appl. Phys. Lett. 96, 053305 (2010)] published Tue Feb 2, 2010.

Pinning induced by inter-domain wall interactions in planar magnetic nanowires

T. J. Hayward, M. T. Bryan, P. W. Fry, P. M. Fundi, M. R. J. Gibbs et al.
We have investigated pinning potentials created by inter-domain wall magnetostatic interactions in planar magnetic nanowires. We show that these potentials can take the form of an energy barrier or an energy well depending on the walls' relative monopole moments, and that the applied magnetic fields ... [Appl. Phys. Lett. 96, 052502 (2010)] published Tue Feb 2, 2010.

Magnetism in Co-doped tris-8-hydroxyquinoline aluminum studied by first-principles calculations

Fenggong Wang, Zhiyong Pang, Liang Lin, Shaojie Fang, Ying Dai et al.
The electronic and magnetic properties of Co-doped tris-8-hydroxyquinoline aluminum (Alq) are studied by first-principles calculations. Our results indicate that the local magnetic moments in doped Alq originate from the localized d states of Co atom. Electron transfer takes place from Co atom to Al ... [Appl. Phys. Lett. 96, 053304 (2010)] published Tue Feb 2, 2010.

Improved crystal quality and performance of GaN-based light-emitting diodes by decreasing the slanted angle of patterned sapphire

Ji-Hao Cheng, YewChung Sermon Wu, Wei-Chih Liao, and Bo-Wen Lin
Periodic triangle pyramidal array patterned sapphire substrates (PSSs) with various slanted angles were fabricated by wet etching. It was found beside normal wurtzite GaN, zinc blende GaN was found on the sidewall surfaces of PSS. The crystal quality and performance of PSS-LEDs improved with decreas ... [Appl. Phys. Lett. 96, 051109 (2010)] published Tue Feb 2, 2010.

X-ray absorption fine structure studies of Mn coordination in doped perovskite SrTiO

I. Levin, V. Krayzman, J. C. Woicik, A. Tkach, and P. M. Vilarinho
The coordination of Mn in doped SrTiO ceramics having nominal compositions SrTiMnO and SrMnTiO was analyzed using x-ray absorption fine structure (XAFS) measurements. As expected, Mn substitution for Ti leads to Mn occupancy of the octahedral B-sites of ABO perovskite lattice with a MnO bond distanc ... [Appl. Phys. Lett. 96, 052904 (2010)] published Tue Feb 2, 2010.

Band offsets of AlO/InGaAs (x=0.53 and 0.75) and the effects of postdeposition annealing

N. V. Nguyen, M. Xu, O. A. Kirillov, P. D. Ye, C. Wang et al.
Band offsets at the interfaces of InGaAs/AlO/Al where x=0.53 and 0.75 were determined by internal photoemission and spectroscopic ellipsometry. The photoemission energy threshold at the InGaAs/AlO interface was found to be insensitive to the indium composition but shifted to a lower energy after a p ... [Appl. Phys. Lett. 96, 052107 (2010)] published Tue Feb 2, 2010.

Effect of vacuum ultraviolet and ultraviolet Irradiation on capacitance-voltage characteristics of low-k-porous organosilicate dielectrics

H. Sinha, J. L. Lauer, M. T. Nichols, G. A. Antonelli, Y. Nishi et al.
High frequency capacitance-voltage (C-V) measurements are used to determine the effects of vacuum ultraviolet (VUV) and ultraviolet (UV) irradiation on defect states in porous low-k organosilicate (SiCOH) dielectrics. The characteristics show that VUV photons depopulate trapped electrons from defect ... [Appl. Phys. Lett. 96, 052901 (2010)] published Tue Feb 2, 2010.

Optical gain improvement in type-II InGaN/GaNSb/GaN quantum well structures composed of InGaN/and GaNSb layers

Seoung-Hwan Park, Doyeol Ahn, Bun-Hei Koo, and Jae-Eung Oh
Optical gain characteristics of type-II InGaN/GaNSb quantum well (QW) structure are investigated by using the multiband effective mass theory. These results are compared with those of conventional InGaN/GaN QW structures. The transition wavelength rapidly increases with increasing the Sb composition ... [Appl. Phys. Lett. 96, 051106 (2010)] published Tue Feb 2, 2010.

Subwavelength plastic wire terahertz time-domain spectroscopy

Borwen You, Ja-Yu Lu, Tze-An Liu, Jin-Long Peng, and Ci-Ling Pan
This work demonstrates the feasibility of a terahertz time-domain spectrometer based on a subwavelength-diameter plastic wire (SPW) for sensing applications. The dispersion property of the SPW is experimentally and theoretically studied. The SPW exhibits a low and controllable waveguide dispersion, ... [Appl. Phys. Lett. 96, 051105 (2010)] published Mon Feb 1, 2010.

Electron energy band alignment at the (100)Si/MgO interface

V. V. Afanas'ev, A. Stesmans, K. Cherkaoui, and P. K. Hurley
The electron energy band diagram at the (100)Si/MgO interface is characterized using internal photoemission of electrons and holes from Si into the oxide. For the as-deposited amorphous MgO the interface barriers correspond to a band gap width of 6.1 eV, i.e., much lower than the conventionally assu ... [Appl. Phys. Lett. 96, 052103 (2010)] published Mon Feb 1, 2010.

Anisotropic relaxation and crystallographic tilt in BiFeO on miscut SrTiO (001)

Rebecca J. Sichel, Alexei Grigoriev, Dal-Hyun Do, Seung-Hyub Baek, Ho-Won Jang et al.
Epitaxial BiFeO thin films on miscut (001) SrTiO substrates relax via mechanisms leading to an average rotation of the crystallographic axes of the BiFeO layer with respect to the substrate. The angle of the rotation reaches a maximum in the plane defined by the surface normal of the film and the di ... [Appl. Phys. Lett. 96, 051901 (2010)] published Mon Feb 1, 2010.

Yellow-green light-emitting electrochemical cells with long lifetime and high efficiency

Andreas Sandstrom, Piotr Matyba, and Ludvig Edman
We show that the electrochemical stability window of the constituent components in light-emitting electrochemical cells (LECs), e.g., the electrolyte, should be considered in order to minimize undesired side reactions. By designing and operating LECs in accordance with straightforward principles, we ... [Appl. Phys. Lett. 96, 053303 (2010)] published Mon Feb 1, 2010.

Electron spin filtering by thin GaNAs/GaAs multiquantum wells

Y. Puttisong, X. J. Wang, I. A. Buyanova, H. Carrere, F. Zhao et al.
Effectiveness of the recently discovered defect-engineered spin-filtering effect is closely examined in GaNAs/GaAs multiquantum wells (QWs) as a function of QW width. In spite of narrow well widths of 39 nm, rather efficient spin filtering is achieved at room temperature. It leads to electron spin p ... [Appl. Phys. Lett. 96, 052104 (2010)] published Mon Feb 1, 2010.

Atomically-thin crystalline films and ribbons of bismuth telluride

Desalegne Teweldebrhan, Vivek Goyal, Muhammad Rahman, and Alexander A. Balandin
The authors report on graphene-like exfoliation of the large-area crystalline films and ribbons of bismuth telluride with the thicknesses of a few atoms. It is demonstrated that BiTe crystal can be mechanically separated into its building blocksTeBiTeBiTe atomic fivefoldswith the thickness of ~1 nm ... [Appl. Phys. Lett. 96, 053107 (2010)] published Mon Feb 1, 2010.

Strong tensile strain induced charge/orbital ordering in (001)-LaSrMnO thin film on 0.7Pb(MgNb)O0.3PbTiO

J. Wang, F. X. Hu, R. W. Li, J. R. Sun, and B. G. Shen
The substrate-induced strain effect in LaSrMnO (LSMO) thin films grown on (001)-oriented SrTiO and ferroelectric 0.7Pb(MgNb)O0.3PbTiO (PMN-PT) substrates was investigated. A metal-insulator transition was observed at low temperature in LSMO/PMN-PT, which was ascribed to charge/orbital ordering (COO) ... [Appl. Phys. Lett. 96, 052501 (2010)] published Mon Feb 1, 2010.

Schottky barrier height and conduction mechanisms in ferroelectric bismuth titanate

Fen Liu, Ying Ma, Feng Yang, and Yichun Zhou
Band structure of ferroelectric bismuth titanate is calculated by first-principles computations under the framework of density functional theory. Using the metal induced gap state model, the Schottky barrier height on Pt electrode is estimated to be as high as 1.26 eV, which indicates that the Schot ... [Appl. Phys. Lett. 96, 052102 (2010)] published Mon Feb 1, 2010.

Cyclodextrins: Promising candidate media for high-capacity hydrogen adsorption

Haiyan Zhu, Yongning Liu, Yuanzhen Chen, and Zhenyi Wen
Cyclodextrins (CDs) found with inexpensive starch are in a particular hollow and truncated cone-type configuration. First-principles calculations indicate that a single alpha-CD can adsorb up to 48 hydrogen molecules by the influence of the oxygen structures in the alpha-CD's hydroxyl (-OH) and epox ... [Appl. Phys. Lett. 96, 054101 (2010)] published Mon Feb 1, 2010.

Collection of suspended particles in a drop using low frequency vibration

James Whitehill, Adrian Neild, Tuck Wah Ng, and Mark Stokes
Particle collection at low frequencies has been erstwhile demonstrated with dry particles and particles floating on the liquid surface. Nevertheless, the ability to collect suspended particles in a fluid offers arguably wider usage in the context of microfluidic or lab-on-a-chip systems. This is dem ... [Appl. Phys. Lett. 96, 053501 (2010)] published Mon Feb 1, 2010.

ZnO nanowires array p-n homojunction and its application as a visible-blind ultraviolet photodetector

Y. H. Leung, Z. B. He, L. B. Luo, C. H. A. Tsang, N. B. Wong et al.
We demonstrated a simple and low-cost fabrication of ZnO p-n homojunction. The junction consists of n-type ZnO nanowires array by a hydrothermal method covered with p-type Al, N co-doped ZnO film by a sol-gel method. The junction exhibits good rectification characteristics, with reverse leakage curr ... [Appl. Phys. Lett. 96, 053102 (2010)] published Mon Feb 1, 2010.

Acoustic band gaps in phononic crystal strip waveguides

Feng-Chia Hsu, Chiung-I Lee, Jin-Chen Hsu, Tsun-Che Huang, Chin-Hung Wang et al.
We study the elastic wave propagation in phononic-crystal strip waveguides cut from a silicon phononic-crystal plate with square-lattice vacuum holes through analyzing the band structure and transmission spectra. We show the influence of different cutting ways is crucial to the band-gap formation, a ... [Appl. Phys. Lett. 96, 051902 (2010)] published Mon Feb 1, 2010.

Dual-mode operation of flexible piezoelectric polymer diaphragm for intracranial pressure measurement

Chunyan Li, Pei-Ming Wu, Lori A. Shutter, and Raj K. Narayan
The dual-mode operation of a polyvinylidene fluoride trifluoroethylene (PVDF-TrFE) piezoelectric polymer diaphragm, in a capacitive or resonant mode, is reported as a flexible intracranial pressure (ICP) sensor. The pressure sensor using a capacitive mode exhibits a higher linearity and less power c ... [Appl. Phys. Lett. 96, 053502 (2010)] published Mon Feb 1, 2010.

Size-dependent recombination dynamics in ZnO nanowires

J. S. Reparaz, F. Guell, M. R. Wagner, A. Hoffmann, A. Cornet et al.
A deep understanding of the recombination dynamics of ZnO nanowires (NWs) is a natural step for a precise design of on-demand nanostructures based on this material system. In this work we investigate the influence of finite-size on the recombination dynamics of the neutral bound exciton around 3.365 ... [Appl. Phys. Lett. 96, 053105 (2010)] published Mon Feb 1, 2010.

Binary liquid crystal alignments based on photoalignment in azo dye-doped liquid crystals and their application

Andy Ying-Guey Fuh, Ju-Chin Chen, San-Yi Huang, and Ko-Ting Cheng
This work demonstrates the feasibility of binary liquid crystal (LC) alignments, in which two forms of LC alignment are in a single pixel or a specific area using a surface-treated alignment layer and a photoalignment film of the adsorption of azo dyes onto the polymer surface in azo dye-doped liqui ... [Appl. Phys. Lett. 96, 051103 (2010)] published Mon Feb 1, 2010.

Mass density of individual cobalt nanowires

L. Philippe, B. Cousin, Zhao Wang, D. F. Zhang, and J. Michler
The mass density of nanowires is determined using in situ resonance frequency experiments combined with quasistatic nanotensile tests. Our results reveal an average mass density of 7.36 g/cm, which is below the theoretical density of bulk cobalt. The results are discussed in terms of the measuremen ... [Appl. Phys. Lett. 96, 051903 (2010)] published Mon Feb 1, 2010.

Enormously high-peak-power optical pulse generation from a single-transverse-mode GaInN blue-violet laser diode

Masaru Kuramoto, Tomoyuki Oki, Tomoya Sugahara, Shunsuke Kono, Masao Ikeda et al.
We have demonstrated extraordinary optical pulse generation with a peak-power of 55 W and pulse duration of 15 ps by intense electrical pulse excitation of a 401 nm GaInN laser diode (LD). Electrical pulse excitation of a GaInN LD which contained a thicker electron blocking layer gave rise to abnorm ... [Appl. Phys. Lett. 96, 051102 (2010)] published Mon Feb 1, 2010.

High-performance surface-enhanced Raman scattering sensors based on Ag nanoparticles-coated Si nanowire arrays for quantitative detection of pesticides

X. T. Wang, W. S. Shi, G. W. She, L. X. Mu, and S. T. Lee
A surface-enhanced Raman scattering (SERS) sensor made of Ag nanoparticles-coated Si nanowire (SiNW) arrays was fabricated for the quantitative detection of Carbaryl (an important nitrogen pesticide). H-terminated SiNWs were capable of reducing silver ions, leading to uniform deposition of silver na ... [Appl. Phys. Lett. 96, 053104 (2010)] published Mon Feb 1, 2010.

Thermal stability of organic thin-film transistors with self-assembled monolayer dielectrics

Kenjiro Fukuda, Tomoyuki Yokota, Kazunori Kuribara, Tsuyoshi Sekitani, Ute Zschieschang et al.
We have investigated the annealing effects on 2 V-operation pentacene organic thin-film transistors (TFTs) with self-assembled monolayer-based gate dielectrics. When pentacene TFTs without passivation layers are annealed at 100 degrees C, the pentacene crystal structure changes to the bulk phase, r ... [Appl. Phys. Lett. 96, 053302 (2010)] published Mon Feb 1, 2010.

Nanophononic thin-film filters and mirrors studied by picosecond ultrasonics

N. D. Lanzillotti-Kimura, B. Perrin, A. Fainstein, B. Jusserand, and A. Lemaitre
Optimized acoustic phonon thin-film filters are studied by picosecond ultrasonics. A broadband mirror and a color filter based on aperiodic multilayers were optimized to work in the subterahertz range, and grown by molecular beam epitaxy. Time resolved differential optical reflectivity experiments w ... [Appl. Phys. Lett. 96, 053101 (2010)] published Mon Feb 1, 2010.

Organic light-emitting diodes containing multilayers of organic single crystals

Hajime Nakanotani and Chihaya Adachi
Double-heterostructure (DH) organic light-emitting diodes (OLEDs) with thick carrier transport layers based on organic single crystals have been fabricated. Although the total thickness of the organic layers (~1.4 [mu]m) is one order of magnitude greater than that of conventional thin-film OLEDs, a ... [Appl. Phys. Lett. 96, 053301 (2010)] published Mon Feb 1, 2010.

Multimode resonances in metallically confined square-resonator microlasers

Kai-Jun Che, Yue-De Yang, and Yong-Zhen Huang
Directional emission InP/AlGaInAs square-resonator microlasers with a side length of 20 [mu]m are fabricated by standard photolithography and inductively coupled-plasma etching technique. Multimode resonances with about seven distinct mode peaks in a free-spectral range are observed from 1460 to 15 ... [Appl. Phys. Lett. 96, 051104 (2010)] published Mon Feb 1, 2010.

Nanoscale resistive memory with intrinsic diode characteristics and long endurance

Kuk-Hwan Kim, Sung Hyun Jo, Siddharth Gaba, and Wei Lu
We report studies on nanoscale resistive memory devices that exhibit diodelike I-V characteristics at on-state with reverse bias current suppressed to below 10 A and rectifying ratio >10. The intrinsic diodelike characteristics are robust during device operation and can survive >10 write/erase progr ... [Appl. Phys. Lett. 96, 053106 (2010)] published Mon Feb 1, 2010.

Sorption properties of NO gas and its strong influence on hole concentration of H-terminated diamond surfaces

Michal Kubovic, Makoto Kasu, and Hiroyuki Kageshima
The hole concentration of hydrogen-terminated diamond surfaces was studied during exposure to different concentrations of NO gas. The hole concentration increased during adsorption of NO molecules on the diamond surface, and decreased when the exposure stopped and NO molecules desorbed from the surf ... [Appl. Phys. Lett. 96, 052101 (2010)] published Mon Feb 1, 2010.

Enhancement of ferromagnetism in Pd nanoparticle by swift heavy ion irradiation

P. K. Kulriya, B. R. Mehta, D. K. Avasthi, D. C. Agarwal, P. Thakur et al.
In this study, the effect of swift heavy ion irradiation on the magnetic properties of the Pd nanoparticles has been investigated. Structural investigations along with superconducting quantum interface device measurements show that ferromagnetic properties of the Pd nanoparticles are due to the devi ... [Appl. Phys. Lett. 96, 053103 (2010)] published Mon Feb 1, 2010.

Wavelength-stable cyan and green light emitting diodes on nonpolar m-plane GaN bulk substrates

Theeradetch Detchprohm, Mingwei Zhu, Yufeng Li, Liang Zhao, Shi You et al.
We report the development of 480 nm cyan and 520 nm green light emitting diodes (LEDs) with a highly stable emission wavelength. The shift is less than 3 nm when the drive current density is changed from 0.1 to 38 A/cm. LEDs have been obtained in GaInN-based homoepitaxy on nonpolar m-plane GaN bulk ... [Appl. Phys. Lett. 96, 051101 (2010)] published Mon Feb 1, 2010.

Optical loss compensation in a bulk left-handed metamaterial by the gain in quantum dots

Zheng-Gao Dong, Hui Liu, Tao Li, Zhi-Hong Zhu, Shu-Ming Wang et al.
A bulk left-handed metamaterial with fishnet structure is investigated to show the optical loss compensation via surface plasmon amplification with the assistance of the gain medium of PbS quantum dots. Simultaneously negative permittivity and permeability are confirmed at the telecommunication wave ... [Appl. Phys. Lett. 96, 044104 (2010)] published Fri Jan 29, 2010.

Plasma characterization using terahertz-wave-enhanced fluorescence

Jingle Liu and X.-C. Zhang
We demonstrate that the terahertz-wave-enhanced fluorescence emission from excited atoms or molecules can be employed in the characterization of laser-induced gas plasmas. The electron relaxation time and plasma density were deduced through applying the electron impact excitation/ionization and elec ... [Appl. Phys. Lett. 96, 041505 (2010)] published Fri Jan 29, 2010.

Universal and reconfigurable logic gates in a compact three-terminal resonant tunneling diode

L. Worschech, F. Hartmann, T. Y. Kim, S. Hofling, M. Kamp et al.
Submicron-sized mesas of resonant tunneling diodes (RTDs) with split drain contacts have been realized and the current-voltage characteristics have been studied in the bistable regime at room temperature. Dynamically biased, the RTDs show noise-triggered firing of spikelike signals and can act as re ... [Appl. Phys. Lett. 96, 042112 (2010)] published Fri Jan 29, 2010.

Time resolved photoluminescence of In(N)As quantum dots embedded in GaIn(N)As/GaAs quantum well

M. Syperek, R. Kudrawiec, M. Baranowski, G. Sek, J. Misiewicz et al.
Carrier dynamics in In(N)As quantum dots embedded in GaIn(N)As quantum well has been studied by time resolved photoluminescence. We have shown that incorporation of nitrogen into InAs/InGaAs system caused a redshift of the ground state emission due to the change in the energy gap and strain distribu ... [Appl. Phys. Lett. 96, 041911 (2010)] published Fri Jan 29, 2010.

Electrical characteristics of an organic bistable device using an Al/Alq/nanostructured MoO/Alq/p-Si structure

Tzu-Yueh Chang, You-Wei Cheng, and Po-Tsung Lee
The electrical properties of a device with an Al/Alq/nanostructured MoO/Alq/p-Si structure were investigated for organic resistance switching memories. The conductance of the device can be electrically switched to either high conductance or low conductance. The bistable switching of the device is at ... [Appl. Phys. Lett. 96, 043309 (2010)] published Fri Jan 29, 2010.

Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

Hoon Eui Jeong, Jin-Kwan Lee, Moon Kyu Kwak, Sang Heup Moon, and Kahp Yang Suh
We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0 degrees to 45 degrees and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and ... [Appl. Phys. Lett. 96, 043704 (2010)] published Fri Jan 29, 2010.

Microstructure, optical, and electrical properties of p-type SnO thin films

W. Guo, L. Fu, Y. Zhang, K. Zhang, L. Y. Liang et al.
SnO thin films were fabricated by electron beam evaporation on (100) Si and c- and r-plane AlO substrates. The films grown at 25 degrees C are nanocrystalline, while the films grown at 600 degrees C are epitaxial on r-plane AlO and (001) textured on Si and c-plane AlO. The SnO films have an optica ... [Appl. Phys. Lett. 96, 042113 (2010)] published Fri Jan 29, 2010.

First contact-charging of gold nanoparticles by electrostatic force microscopy

D. Prime and S. Paul
The use of nanoparticle materials in the manufacture of electronic polymer memory devices is on the rise. Organic memory devices are fabricated by depositing a blend of organic polymer, small organic molecules, and nanoparticles between two metal electrodes. The primary aim is to produce devices tha ... [Appl. Phys. Lett. 96, 043120 (2010)] published Fri Jan 29, 2010.

Eddy current induced magnetoelectricity in a piezoelectric unimorph bender

B. Guiffard, D. Guyomar, L. Garbuio, R. Belouadah, J. Zhang et al.
Here, we report on a magnetoelectric (ME) coupling in a simple piezoelectric unimorph bender induced by the eddy currents within the silver electrodes of the piezoelectric ceramic Pb(Zr,Ti)O (PZT) subjected to ac magnetic flux. Eddy currents and the applied magnetic field generate Lorentz forces in ... [Appl. Phys. Lett. 96, 044105 (2010)] published Fri Jan 29, 2010.

Application of negative differential conductance in Al/AlO single-electron transistors for background charge characterization

Hubert C. George, Mathieu Pierre, Xavier Jehl, Alexei O. Orlov, Marc Sanquer et al.
Negative differential conductance (NDC) is reported in the charging diagram of a normal state metal-metal oxide single electron transistor (SET) fabricated on a quartz substrate. We discuss the physical origin and cause of the observed effect. Using a simple electrostatic model we simulated SET char ... [Appl. Phys. Lett. 96, 042114 (2010)] published Fri Jan 29, 2010.

Ultraflexible amorphous silicon transistors made with a resilient insulator

Lin Han, Katherine Song, Prashant Mandlik, and Sigurd Wagner
The conventional, brittle, silicon nitride barrier layer and gate insulator in amorphous silicon thin-film transistors (a-Si:H TFTs) on 50 [mu]m thick polyimide foil was replaced by a resilient, homogeneous, hybrid of silicon dioxide and silicone polymer. The transistor structures can be bent down ... [Appl. Phys. Lett. 96, 042111 (2010)] published Fri Jan 29, 2010.

Polymer photodetector with voltage-adjustable photocurrent spectrum

En-Chen Chen, Chia-Yu Chang, Ji-Ting Shieh, Shin-Rong Tseng, Hsin-Fei Meng et al.
Polymer photodetectors with voltage-adjustable photoresponse from visible to near infrared range are demonstrated. Poly(3-hexylthiophene) and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) blend is used as the active layer. The photoresponse can be continuously adjusted by the thickness of the ac ... [Appl. Phys. Lett. 96, 043507 (2010)] published Fri Jan 29, 2010.

Probing atomic rearrangement events in resistive switching nanostructures

J. Ventura, J. P. Araujo, J. B. Sousa, Y. Liu, Z. Zhang et al.
Resistive switching in metal-insulator-metal structures is being investigated aiming next generation nonvolatile memories. We studied the time evolution of the electrical resistance (R) of Ta/AlO/Ta nanostructures displaying resistive switching. At low temperature and in the early switching stages w ... [Appl. Phys. Lett. 96, 043505 (2010)] published Fri Jan 29, 2010.

Resistivity dominated by surface scattering in sub-50 nm Cu wires

R. L. Graham, G. B. Alers, T. Mountsier, N. Shamma, S. Dhuey et al.
Electron scattering mechanisms in copper lines were investigated to understand the extendibility of copper interconnects when linewidth or thickness is less than the mean free path. Electron-beam lithography and a dual hard mask were used to produce interconnects with linewidths between 25 and 45 nm ... [Appl. Phys. Lett. 96, 042116 (2010)] published Fri Jan 29, 2010.

Influence of random roughness on cantilever curvature sensitivity

O. Ergincan, G. Palasantzas, and B. J. Kooi
In this work we explore the influence of random surface roughness on the cantilever sensitivity to respond to curvature changes induced by changes in surface stress. The roughness is characterized by the out-of-plane roughness amplitude w, the lateral correlation length xi, and the roughness or Hurs ... [Appl. Phys. Lett. 96, 041912 (2010)] published Fri Jan 29, 2010.

Parasitic capacitance effect on programming performance of phase change random access memory devices

E. G. Yeo, L. P. Shi, R. Zhao, K. G. Lim, T. C. Chong et al.
Parasitic capacitance has increasing implications on the programming performance of phase change random access memory (PCRAM) devices due to increased scaling and high frequency operation. PCRAM devices with larger parasitic capacitance were found to require higher applied voltage to amorphize due t ... [Appl. Phys. Lett. 96, 043506 (2010)] published Fri Jan 29, 2010.

The influence of notches on domain dynamics in ferroelectric nanowires

M. McMillen, R. G. P. McQuaid, S. C. Haire, C. D. McLaughlin, L. W. Chang et al.
The extent to which notches inhibit axial switching of polarization in ferroelectric nanowires was investigated by monitoring the switching behavior of single crystal BaTiO wires before and after patterning triangular notches along their lengths. Static zero-field domain patterns suggested a strong ... [Appl. Phys. Lett. 96, 042904 (2010)] published Fri Jan 29, 2010.

Tunable optical gratings based on buckled nanoscale thin films on transparent elastomeric substrates

Cunjiang Yu, Kevin O'Brien, Yong-Hang Zhang, Hongbin Yu, and Hanqing Jiang
This letter reports a tunable optical grating based on buckled thin film with periodic sinusoidal patterns on a transparent elastomeric substrate. Submicron scale sinusoidal gratings have been fabricated with nanometer thick Gold/Palladium film coated on 30% pretensioned polydimethylsiloxane substra ... [Appl. Phys. Lett. 96, 041111 (2010)] published Fri Jan 29, 2010.

Anisotropy of tensile stresses and cracking in nonbasal plane AlGaN/GaN heterostructures

Erin C. Young, Alexey E. Romanov, Chad S. Gallinat, Asako Hirai, Glenn E. Beltz et al.
AlGaN films grown on nonpolar m {1[overline 1]00} and {11[overline 2]2} semipolar orientations of freestanding GaN substrates were investigated over a range of stress states (x<=0.17). Cracking on the (0001) plane was observed beyond a critical thickness in the {1[overline 1]00} oriented films, whil ... [Appl. Phys. Lett. 96, 041913 (2010)] published Fri Jan 29, 2010.

A route to improved extraction efficiency of light-emitting diodes

H. Zhu, C. X. Shan, L. K. Wang, Y. Yang, J. Y. Zhang et al.
The electroluminescence from an n-MgZnO/i-ZnO/MgO/p-GaN asymmetric double heterojunction has been demonstrated. With the injection of electrons from n-MgZnO and holes from p-GaN, an intense ultraviolet emission coming from the ZnO active layer was observed. It is revealed that the emission intensity ... [Appl. Phys. Lett. 96, 041110 (2010)] published Fri Jan 29, 2010.

Spin-transfer switching in an epitaxial spin-valve nanopillar with a full-Heusler CoFeAlSi alloy

Hiroaki Sukegawa, Shinya Kasai, Takao Furubayashi, Seiji Mitani, and Koichiro Inomata
We report magnetization switching by spin-transfer torque in an epitaxial spin-valve nanopillar made with a half-metallic full-Heusler CoFeAlSi (CFAS) alloy. The CFAS/Ag/CFAS spin valves showed a magnetoresistance ratio of 7%9%, and spin-transfer switching was clearly observed in the nanopillar by a ... [Appl. Phys. Lett. 96, 042508 (2010)] published Fri Jan 29, 2010.

A molecular mechanisms-based biophysical model for two-phase cell spreading

Yue Li, Guang-Kui Xu, Bo Li, and Xi-Qiao Feng
Cell spreading on an extracellular matrix is crucial for many biological functions and processes. By accounting for the molecular mechanisms of actin polymerization and integrin binding between the cell and the extracellular matrix, we here propose a biophysical model to predict the time-dependent g ... [Appl. Phys. Lett. 96, 043703 (2010)] published Fri Jan 29, 2010.

Morphological and topological analysis of coarsened nanoporous gold by x-ray nanotomography

Yu-chen Karen Chen, Yong S. Chu, JaeMock Yi, Ian McNulty, Qun Shen et al.
We used x-ray nanotomography to characterize the three-dimensional (3D) morphology and topology of dealloyed nanoporous gold after coarsening. The interface shape distribution obtained from the nanotomography measurement shows that the coarsening does not proceed by bulk diffusion. The surface norma ... [Appl. Phys. Lett. 96, 043122 (2010)] published Fri Jan 29, 2010.

Single cell manipulation using ferromagnetic composite microtransporters

Mahmut Selman Sakar, Edward B. Steager, Dal Hyung Kim, Min Jun Kim, George J. Pappas et al.
For biomedical applications, such as single cell manipulation, it is important to fabricate microstructures that can be powered and controlled wirelessly in fluidic environments. In this letter, we describe the construction and operation of truly micron-sized, biocompatible ferromagnetic microtransp ... [Appl. Phys. Lett. 96, 043705 (2010)] published Fri Jan 29, 2010.

Enhanced ferromagnetism in HO-treated p-(ZnMn)O layer

Sejoon Lee, Yoon Shon, Deuk Young Kim, Tae Won Kang, and Chong S. Yoon
Enhanced ferromagnetism was observed from the HO-treated p-type (ZnMn)O:As layer. Compared with the untreated sample, the HO-treated sample showed the enlarged ferromagnetic hysteresis loop with approximately two-times-increased spontaneous magnetization. And also, in comparison with the untreated s ... [Appl. Phys. Lett. 96, 042115 (2010)] published Fri Jan 29, 2010.

Structural and dynamical heterogeneity in molten Si-rich oxides

S. Q. Wu, C. Z. Wang, Z. Z. Zhu, and K. M. Ho
Ab initio molecular dynamics simulations are performed to study the structural and dynamical properties of molten Si oxides. Segregation of SiO (y<2) and pure Si network are clearly observed in the Si-rich oxide liquids. The size of Si-aggregate regions increases with increasing Si composition. The ... [Appl. Phys. Lett. 96, 043121 (2010)] published Fri Jan 29, 2010.

Form birefringence metal and its plasmonic anisotropy

Liang Feng, Zhaowei Liu, Vitaliy Lomakin, and Yeshaiahu Fainman
We constructed a uniaxial form birefringence metal that exhibits different dielectric polarizabilities along different optical axes as well as its supported optical anisotropy of surface plasmon polariton waves. The generated plasmonic index ellipsoid that exists in reciprocal space has been directl ... [Appl. Phys. Lett. 96, 041112 (2010)] published Fri Jan 29, 2010.

Annealing effects of in-depth profile and band discontinuity in TiN/LaO/HfSiO/SiO/Si gate stack structure studied by angle-resolved photoemission spectroscopy from backside

S. Toyoda, H. Kamada, T. Tanimura, H. Kumigashira, M. Oshima et al.
We have investigated annealing effects on in-depth profile and band discontinuity for a metal gate/high-k gate stack structure on a Si substrate using backside angle-resolved photoemission spectroscopy with synchrotron radiation. In-depth profiles analyzed from angle-resolved photoemission spectrosc ... [Appl. Phys. Lett. 96, 042905 (2010)] published Fri Jan 29, 2010.

Improvement of the computation of Fourier integrals using the complex plane: Application to acoustic fields

Philippe Gatignol, Catherine Potel, and Nacera Bedrici
This letter aims at showing the interest in using an integration path in the complex plane in order to calculate Fourier integrals, instead of using a real path, as needed for the fast Fourier transform algorithm as follows: fastness, accuracy, avoiding of singularities, or even aliasing phenomenon. ... [Appl. Phys. Lett. 96, 044103 (2010)] published Fri Jan 29, 2010.

Investigation of JahnTeller splitting with O 1s x-ray absorption spectroscopy in strained NdCaMnO thin films

Daniel Hsu, Y. S. Chen, M. Y. Song, C. H. Chuang, Minn-Tsong Lin et al.
Electronic structures of strained NdCaMnO (NCMO) thin films with x=0 to 0.8 are investigated via x-ray absorption spectroscopy (XAS). The obtained O 1s spectra within the photon energy 529535 eV can be decomposed into e[up-arrow], e[up-arrow], t[down-arrow], and e[down-arrow] bands. Based on the as ... [Appl. Phys. Lett. 96, 041914 (2010)] published Fri Jan 29, 2010.