Applied Physics Letters: All Topics

The effect of dielectric constant on device mobilities of high-performance, flexible organic field effect transistors

H. S. Tan, N. Mathews, T. Cahyadi, F. R. Zhu, and S. G. Mhaisalkar
High-performance pentacene ([mu]=6.3 cm/V s) and poly(3-hexylthiophene) ([mu]=0.43 cm/V s) field effect transistors have been realized on flexible substrate with low operating voltage (<5 V), utilizing a trilayer sol-gel silica gate dielectric. Furthermore, the permittivity of the dielectric was ... [Appl. Phys. Lett. 94, 263303 (2009)] published Thu Jul 2, 2009.

Tunneling field-effect transistor with epitaxial junction in thin germanium-on-insulator

D. Kazazis, P. Jannaty, A. Zaslavsky, C. Le Royer, C. Tabone et al.
We report on the fabrication and electrical characterization at room and low temperatures of a tunneling field-effect transistor (TFET). The devices are fabricated in thin germanium-on-insulator and consist of a heavily p-doped, epitaxially grown source, a heavily n-doped ion implanted drain, and a ... [Appl. Phys. Lett. 94, 263508 (2009)] published Thu Jul 2, 2009.

Atomic layer deposition of ZrO/LaO high-k dielectrics on germanium reaching 0.5 nm equivalent oxide thickness

S. Abermann, O. Bethge, C. Henkel, and E. Bertagnolli
We investigate ultrathin ZrO/LaO high-k dielectric stacks on germanium grown by atomic layer deposition. LaO is deposited from tris(N,N-diisopropylformamidinate)-lanthanum and oxygen. Interfacial layer-free oxide stacks with a relative dielectric constant of 21 and equivalent oxide thickness values ... [Appl. Phys. Lett. 94, 262904 (2009)] published Thu Jul 2, 2009.

A comparison of the ideal strength between L1Co(Al,W) and NiAl under tension and shear from first-principles calculations

Yun-Jiang Wang and Chong-Yu Wang
The ideal strengths of L1Co(Al,W) in comparison with NiAl are investigated using the first-principles method. Results for the stress-strain relationships, ideal tensile and shear strengths are presented. The calculated elastic properties agree well with the experimental observations. Co(Al,W) is fou ... [Appl. Phys. Lett. 94, 261909 (2009)] published Thu Jul 2, 2009.

Tunneling interlayer exchange coupling between oxide ferrimagnets: Analysis for FeO/vac/FeO case

Han-Chun Wu, O. N. Mryasov, K. Radican, and I. V. Shvets
We have investigated tunneling interlayer exchange coupling (TIEC) between ferrimagnetic FeO films via a tunneling barrier. In this investigation we employ ab initio density functional theory to study a generic tunneling junction incorporating ferrimagnets FeO/vac/FeO. In contrast with previously es ... [Appl. Phys. Lett. 94, 262506 (2009)] published Thu Jul 2, 2009.

Plasmonic optical antennas on dielectric gratings with high field enhancement for surface enhanced Raman spectroscopy

Jingjing Li, David Fattal, and Zhiyong Li
We present a rational approach toward amplifying the local electromagnetic (EM) field for surface enhanced Raman spectroscopy applications by integrating dielectric gratings capable of guided mode resonance with plasmonic optical antennas. The optical antennas are placed periodically at certain posi ... [Appl. Phys. Lett. 94, 263114 (2009)] published Thu Jul 2, 2009.

Temperature dependence of the magnetoresistance in Fe/MgO core/shell nanoparticles

C. Martinez-Boubeta, Ll. Balcells, S. Valencia, D. Schmitz, C. Monty et al.
The temperature dependence of magnetoresistance (MR) of powdered samples consisting of spherical Fe/MgO core/shell nanoparticles was analyzed. A change of the MR from normal at room temperature to inverse at low temperatures was observed. Concomitant with this, samples showed a sudden increase in th ... [Appl. Phys. Lett. 94, 262507 (2009)] published Thu Jul 2, 2009.

On the lateral crystal growth of laser irradiated NiTi thin films

A. J. Birnbaum, Y. Lawrence Yao, U.-J. Chung, James. S. Im, X. Huang et al.
This letter demonstrates the ability to induce laterally grown, large-aspect crystals via pulsed, melt-mediated laser crystallization in NiTi thin films. Sputter-deposited 200 nm NiTi films were pulse irradiated utilizing a homogenized 308 nm excimer beam over a series of varying incident laser ener ... [Appl. Phys. Lett. 94, 261908 (2009)] published Thu Jul 2, 2009.

Surface intercalation of gold underneath a graphene monolayer on SiC(0001) studied by scanning tunneling microscopy and spectroscopy

B. Premlal, M. Cranney, F. Vonau, D. Aubel, D. Casterman et al.
The effects of gold deposition on monolayer graphene (MG) epitaxied on SiC (0001) substrate are examined via scanning tunneling microscopy and scanning tunneling spectroscopy (STS). Two types of surfaces with distinctive topography are demonstrated: (i) intercalated gold clusters having no interacti ... [Appl. Phys. Lett. 94, 263115 (2009)] published Thu Jul 2, 2009.

Nd-doped silicon nanowires with room temperature ferromagnetism and infrared photoemission

Wei-Fan Lee, Chung-Yang Lee, Mei-Lin Ho, Chi-Te Huang, Chen-Ho Lai et al.
Nd-doped silicon nanowires have been synthesized by a vapor transport and condensation method. The incorporation of neodymium within silicon nanowires was achieved by using NdCl6HO powder as the doping source. Ferromagnetism and infrared photoluminescence at room temperature were discovered. The sig ... [Appl. Phys. Lett. 94, 263117 (2009)] published Thu Jul 2, 2009.

Seeing structures and measuring properties with transmission electron microscopy images: A simple combination to study size effects in nanoparticle systems

Patricia Donnadieu, Sorin Lazar, Gianluigi A. Botton, Isabelle Pignot-Paintrand, Michael Reynolds et al.
We report on a method to measure the mean inner potential (V) using transmission electron microscopy. It is based on phase retrieval from a focus series and has allowed to measure V as a function of the size for a system of gold nanoparticles. It comes out that V increases for particles below 2 nm. ... [Appl. Phys. Lett. 94, 263116 (2009)] published Thu Jul 2, 2009.

Probing negative differential resistance on Si(111)-sqrt(3) x sqrt(3)-Ag surface with scanning tunneling microscopy

Weihua Wang, Aidi Zhao, Bing Wang, and J. G. Hou
We present our study on the Si(111)-sqrt(3) x sqrt(3)-Ag surface using scanning tunneling microscopy/spectroscopy. The results reveal that the well defined localized surface-state bands S/S in the surface with lightly doped Si substrate play an important role in electron transport. The relative wide ... [Appl. Phys. Lett. 94, 262108 (2009)] published Thu Jul 2, 2009.

Electron inelastic mean free paths for carbon nanotubes from optical data

Ioanna Kyriakou, Dimitris Emfietzoglou, Rafael Garcia-Molina, Isabel Abril, and Kostas Kostarelos
We present a simple model dielectric response function for both bulk and individual carbon nanotubes based on a parameterization of experimental optical data and analytic dispersion relations that account for dimensionality and linewidth broadening. The model is used to calculate electron inelastic ... [Appl. Phys. Lett. 94, 263113 (2009)] published Thu Jul 2, 2009.

Erratum: Multiwavelength Solc filters based on chi nonlinear quasiperiodic photonic crystals with Fibonacci sequences [Appl. Phys. Lett. 91, 251110 (2007)]

Chul-Sik Kee, Jongmin Lee, and Yeung Lak Lee
Abstract not available. [Appl. Phys. Lett. 94, 269904 (2009)] published Thu Jul 2, 2009.

Broadband moth-eye antireflection coatings fabricated by low-cost nanoimprinting

Q. Chen, G. Hubbard, P. A. Shields, C. Liu, D. W. E. Allsopp et al.
Subwavelength scale antireflection moth-eye structures in silicon were fabricated by a wafer-scale nanoimprint technique and demonstrated an average reflection of 1% in the spectral range from 400 to 1000 nm at normal incidence. An excellent antireflection property out to large incident angles is sh ... [Appl. Phys. Lett. 94, 263118 (2009)] published Thu Jul 2, 2009.

Thermal stability of Cu and Fe nitrides and their applications for writing locally spin valves

C. Navio, J. Alvarez, M. J. Capitan, J. Camarero, and R. Miranda
We have studied the thermal stability of the Cu and Fe nitrides. These results show that a nanometer-thick Cu nitride film decomposes at the FeN growth temperature. Considering this, we propose for their use in spintronics, the room temperature growth of a nonmagnetic (FeN)/semiconducting (CuN) epit ... [Appl. Phys. Lett. 94, 263112 (2009)] published Thu Jul 2, 2009.

Size effects in submicron exchange bias square elements

G. Vallejo-Fernandez and J. N. Chapmam
The behavior of submicron exchange bias square elements has been investigated for systems containing metallic polycrystalline layers. Numerical simulations using a simple theoretical model show that the exchange bias for such elements can increase and/or decrease depending on the microstructure of t ... [Appl. Phys. Lett. 94, 262508 (2009)] published Thu Jul 2, 2009.

Trimethylamine biosensor based on pentacene enzymatic organic field effect transistor

A. K. Diallo, J. Tardy, Z. Q. Zhang, F. Bessueille, N. Jaffrezic-Renault et al.
This paper reports on an enzymatic organic field effect transistor based biosensor dedicated to the detection of trimethylamine, in view of fish freshness assessment. Flexible devices were processed on Kapton substrate with pentacene as organic semiconductor and Parylene-C as top gate dielectric. Pr ... [Appl. Phys. Lett. 94, 263302 (2009)] published Thu Jul 2, 2009.

Self-assembled bioinspired quantum dots: Optical properties

N. Amdursky, M. Molotskii, E. Gazit, and G. Rosenman
Until now, the wide research field of quantum dots (QDs) focused on inorganic structures. In the present study, we report on quantum confinement phenomena found in peptide nanocrystalline regions formed within self-assembly peptide nanospheres. These bioinspired nanostructures exhibit the optical ab ... [Appl. Phys. Lett. 94, 261907 (2009)] published Thu Jul 2, 2009.

Replicated photonic crystals by atomic layer deposition within holographically defined polymer templates

E. Graugnard, O. M. Roche, S. N. Dunham, J. S. King, D. N. Sharp et al.
We report the replication of holographically defined photonic crystals using multistage atomic layer deposition. Low- and high-temperature atomic layer depositions were combined with selective etching to deposit and remove multiple conformal thin films within three-dimensional polymer templates. Usi ... [Appl. Phys. Lett. 94, 263109 (2009)] published Wed Jul 1, 2009.

Characterization of blue-green m-plane InGaN light emitting diodes

You-Da Lin, Arpan Chakraborty, Stuart Brinkley, Hsun Chih Kuo, Thiago Melo et al.
High indium content blue-green (460520 nm) m-plane InGaN light emitting diodes (LEDs) were grown on low defect-density m-plane GaN substrates. Systematic studies were performed on packaged blue-green LED lamps by using a range of well and barrier thicknesses. Photoluminance and electroluminance peak ... [Appl. Phys. Lett. 94, 261108 (2009)] published Wed Jul 1, 2009.

Transient charge trapping and detrapping properties of a thick SiO/AlO stack studied by short single pulse I-V

Man Chang, Minseok Jo, Seungjae Jung, Joonmyoung Lee, Sanghun Jeon et al.
The transient charge trapping and detrapping of a thick SiO/AlO gate oxide device has been evaluated by single pulse I-V (PIV). During the period of a single pulse, we observed fast electron detrapping. This occurred through the gate electrode, causing a counterclockwise PIV hysteresis despite elect ... [Appl. Phys. Lett. 94, 262107 (2009)] published Wed Jul 1, 2009.

The effects of shell characteristics on the current-voltage behaviors of dye-sensitized solar cells based on ZnO/TiO core/shell arrays

Meili Wang, Changgang Huang, Yongge Cao, Qingjiang Yu, Wang Guo et al.
The ZnO/TiO core/shell structure was formed through deposition of a TiO coating layer on the hydrothermally fabricated ZnO nanorod arrays through radio frequency magnetron sputtering. The effects of the TiO shell's characteristics on the current-voltage behaviors of the core/shell-based dye-sensitiz ... [Appl. Phys. Lett. 94, 263506 (2009)] published Wed Jul 1, 2009.

Electric detection of spin wave resonance using inverse spin-Hall effect

K. Ando, J. Ieda, K. Sasage, S. Takahashi, S. Maekawa et al.
Spin wave resonance in NiFe/Pt thin wire arrays has been investigated using the inverse spin-Hall effect (ISHE). The spin wave in the NiFe layer drives spin pumping, generation of spin currents from magnetization precession, and the pumped spin current is converted into a charge current by ISHE in t ... [Appl. Phys. Lett. 94, 262505 (2009)] published Wed Jul 1, 2009.

Flexible Ge-on-polyimide detectors

W. S. Ho, Y.-H. Dai, Y. Deng, C.-H. Lin, Y.-Y. Chen et al.
A flexible Ge-on-polyimide photodetector is demonstrated. The single crystalline thin film of Ge was transferred on the polyimide by adhesive wafer bonding and smart-cut techniques. A simple tunneling metal-oxide-semiconductor structure is fabricated for the detector applications. Due to the transpa ... [Appl. Phys. Lett. 94, 261107 (2009)] published Wed Jul 1, 2009.

Retention in nonvolatile silicon transistors with an organic ferroelectric gate

Roman Gysel, Igor Stolichnov, Alexander K. Tagantsev, Sebastian W. E. Riester, Nava Setter et al.
A silicone-based one-transistor nonvolatile memory cell has been implemented by integration of a ferroelectric polymer gate on a standard n-type metal oxide semiconductor field effect transistor. The polarization reversal in the gate results in a stable and reproducible memory effect changing the so ... [Appl. Phys. Lett. 94, 263507 (2009)] published Wed Jul 1, 2009.

Erratum: Nonvolatile memory device based on Ag nanoparticle: Characteristics improvement [Appl. Phys. Lett. 94, 173510 (2009)]

Biswanath Mukherjee and Moumita Mukherjee
Abstract not available. [Appl. Phys. Lett. 94, 269903 (2009)] published Wed Jul 1, 2009.

Strain relaxation of SiGe in a Si/SiGe/Si heterostructure under proton irradiation

Z. F. Di, Y. Q. Wang, M. Nastasi, G. Bisognin, M. Berti et al.
We have studied the mechanisms underlying strained layer relaxation by means of point defect interaction. During high temperature (300 degrees C) proton irradiation, vacancies generated in the vicinity of SiGe layer migrate and accumulate within the compressively strained SiGe layer. The accumulati ... [Appl. Phys. Lett. 94, 264102 (2009)] published Wed Jul 1, 2009.

Thermoelectric evaluation of the dopant density of p-type InAs

M. C. Wagener, V. Wagener, and J. R. Botha
Thermoelectric measurements were performed on p-type InAs thin films grown by metalorganic vapor phase epitaxy. The measured Seebeck coefficient displayed an anomalous temperature dependence due to the existence of a highly conductive surface inversion layer. The effect of a degenerate conduction la ... [Appl. Phys. Lett. 94, 262106 (2009)] published Wed Jul 1, 2009.

Doping-dependent nanofaceting on silicon nanowire surfaces

Fang Li, Peter D. Nellist, and David J. H. Cockayne
Silicon nanowires with axially varying n- and p-doping were grown by the vapor-liquid-solid approach using gold as the catalyst. The nanowire sidewalls exhibit periodic nanofaceting, which is found to be dopant-dependent. It is shown that the nanofaceting occurs during the enhanced sidewall growth t ... [Appl. Phys. Lett. 94, 263111 (2009)] published Wed Jul 1, 2009.

Hybrid core-multishell nanowire forests for electrical connector applications

Rehan Kapadia, Hyunhyub Ko, Yu-Lun Chueh, Johnny C. Ho, Toshitake Takahashi et al.
Electrical connectors based on hybrid core-multishell nanowire forests that require low engagement forces are demonstrated. The physical binding and electrical connectivity of the nanowire electrical connectors arise from the van der Waals interactions between the conductive metallic shells of the e ... [Appl. Phys. Lett. 94, 263110 (2009)] published Wed Jul 1, 2009.

Single InAs quantum dot arrays and directed self-organization on patterned GaAs (311)B substrates

E. Selcuk, A. Yu. Silov, and R. Notzel
Formation of laterally ordered single InAs quantum dot (QD) arrays by self-organized anisotropic strain engineering of InGaAs/GaAs superlattice templates on GaAs (311)B by molecular beam epitaxy is achieved through optimization of growth temperature, InAs amount, and annealing. Directed self-organiz ... [Appl. Phys. Lett. 94, 263108 (2009)] published Wed Jul 1, 2009.

Photocurrent properties of freely suspended carbon nanotubes under uniaxial strain

S. M. Kaniber, L. Song, J. P. Kotthaus, and A. W. Holleitner
The photocurrent properties of freely suspended single-walled carbon nanotubes (CNTs) are investigated as a function of uniaxial strain. We observe that at low strain, the photocurrent signal of the CNTs increases for increasing strain, while for large strain, the signal decreases, respectively. We ... [Appl. Phys. Lett. 94, 261106 (2009)] published Wed Jul 1, 2009.

Development of enhancement mode AlN/GaN high electron mobility transistors

C. Y. Chang, S. J. Pearton, C. F. Lo, F. Ren, I. I. Kravchenko et al.
Enhancement mode AlN/GaN high electron mobility transistors (HEMTs) were fabricated from originally depletion-mode structures using oxygen plasma treatment on the gate area prior to the gate metallization. Starting with a depletion mode AlN/GaN HEMT, the threshold voltage of the HEMT could be shifte ... [Appl. Phys. Lett. 94, 263505 (2009)] published Tue Jun 30, 2009.

Thiol-based self-assembly nanostructures in promoting interfacial adhesion for copper-epoxy joint

Cell K. Y. Wong, Matthew M. F. Yuen, and Bing Xu
Adhesion promotion between copper-epoxy interfaces without roughening the copper substrates is critical for new generation electronic devices. This paper demonstrates a pronounced adhesion promotion of a copper-epoxy joint from 4.8 J m for the untreated samples to 159 J m for the interfaces prepar ... [Appl. Phys. Lett. 94, 263102 (2009)] published Tue Jun 30, 2009.

Strong perpendicular magnetic anisotropy in Ni/Co(111) single crystal superlattices

S. Girod, M. Gottwald, S. Andrieu, S. Mangin, J. McCord et al.
Single crystal Ni/Co(111) superlattices have been grown by molecular beam epitaxy. The Ni thickness is 3 ML whereas the Co thickness varies from 0.2 to 4 ML. The superlattices were studied using magnetometry and ferromagnetic resonance spectroscopy and they all exhibit strong perpendicular to the pl ... [Appl. Phys. Lett. 94, 262504 (2009)] published Tue Jun 30, 2009.

Maximal energy that can be converted by a dielectric elastomer generator

Soo Jin Adrian Koh, Xuanhe Zhao, and Zhigang Suo
Mechanical energy can be converted to electrical energy by using a dielectric elastomer generator. The elastomer is susceptible to various modes of failure, including electrical breakdown, electromechanical instability, loss of tension, and rupture by stretch. The modes of failure define a cycle of ... [Appl. Phys. Lett. 94, 262902 (2009)] published Tue Jun 30, 2009.

The influence of temperature and electric field on field emission energy distribution of an individual single-wall carbon nanotube

Ping Wu, N. Y. Huang, S. Z. Deng, S. D. Liang, Jun Chen et al.
The influence of temperature and electric field on field emission energy distribution (FEED) is studied. It is found that higher temperature energizes more higher-energy electrons. FEED peaks shift toward low energy linearly with the increase in applied voltage because of the electric field penetrat ... [Appl. Phys. Lett. 94, 263105 (2009)] published Tue Jun 30, 2009.

Dielectric relaxation and relaxor behavior in bilayered perovskites

Y. Gonzalez-Abreu, A. Pelaiz-Barranco, E. B. Araujo, and A. Franco Junior
SrBaBiNbO ferroelectric ceramics exhibit a complex dielectric behavior, showing typical relaxor behavior. The relaxation processes are described by the ColeCole model [K. S. Cole and R. H. Cole, J. Chem. Phys. 9, 341 (1941)]. At temperatures below 490 K, the dielectric relaxation is associated to th ... [Appl. Phys. Lett. 94, 262903 (2009)] published Tue Jun 30, 2009.

Electronic structure characterization of LaNiMnO epitaxial thin films using synchrotron-radiation photoelectron spectroscopy and optical spectroscopy

M. Kitamura, I. Ohkubo, M. Matsunami, K. Horiba, H. Kumigashira et al.
Electronic structures of LaNiMnO epitaxial films are characterized using synchrotron-radiation photoelectron spectroscopy and optical spectroscopy. X-ray absorption spectra reveal that the valence states of Ni and Mn are dominant. The electronic structure at the valence band maximum is mainly derive ... [Appl. Phys. Lett. 94, 262503 (2009)] published Tue Jun 30, 2009.

Bidirectional current-voltage converters based on magnetostrictive/piezoelectric composites

Yanmin Jia, Siu Wing Or, Helen Lai Wa Chan, Jie Jiao, Haosu Luo et al.
We report a power supply-free, bidirectional electric current-voltage converter based on a coil-wound laminated composite of magnetostrictive alloy and piezoelectric crystal. An electric current applied to the coil induces a magnetic field, resulting in an electric voltage from the composite due to ... [Appl. Phys. Lett. 94, 263504 (2009)] published Tue Jun 30, 2009.

Electronic transport property of single-crystalline hexagonal tungsten trioxide nanowires

S. J. Wang, W. J. Lu, G. Cheng, K. Cheng, X. H. Jiang et al.
Hexagonal WO nanowires were prepared on Si substrate by thermal evaporation of WO powder. A single WO nanowire was assembled on a pair of Pt electrodes by electric field assembly. The electrical transport behavior indicates that the back-to-back SBs structure is formed, which show nonlinear and asym ... [Appl. Phys. Lett. 94, 263106 (2009)] published Tue Jun 30, 2009.

Measuring the profile of the emission zone in polymeric organic light-emitting diodes

Malte C. Gather, Michael Flammich, Norbert Danz, Dirk Michaelis, and Klaus Meerholz
The profile of the emission zone (PEZ) in the emissive layer (EML) of polymeric organic light-emitting diodes (OLEDs) is determined by fitting the measured electroluminescence spectrum of the device with a series of simulated spectra that correspond to different emitter locations. The studied OLEDs ... [Appl. Phys. Lett. 94, 263301 (2009)] published Tue Jun 30, 2009.

A theoretical study on thermoelectric properties of graphene nanoribbons

Yijian Ouyang and Jing Guo
We investigate the thermoelectric properties of graphene nanoribbons (GNRs) by solving atomistic electron and phonon transport equations in the nonequilibrium Green's function formalism. The dependence of thermopower on temperature and chemical potential is compared to that of graphene, which shows ... [Appl. Phys. Lett. 94, 263107 (2009)] published Tue Jun 30, 2009.

Change of the trap energy levels of the atomic layer deposited HfLaO films with different La concentration

Chee-Hong An, Myung Soo Lee, Ju-Yun Choi, and Hyoungsub Kim
Ultrathin HfO and HfLaO films with La/(Hf+La) ratios of 42%, 57%, and 64% were synthesized with an atomic layer deposition process. By measuring the leakage current at different temperatures, the conduction mechanism of HfO and HfLaO films was shown to follow the PooleFrenkel emission model under a ... [Appl. Phys. Lett. 94, 262901 (2009)] published Tue Jun 30, 2009.

Coherent detection of nonlinear nanomechanical motion using a stroboscopic downconversion technique

Quirin P. Unterreithmeier, Stephan Manus, and Jorg P. Kotthaus
A method is presented that overcomes bandwidth limitations arising in a fiber-optic setup transducing mechanical motion. The reflected light from a sample incorporating a nanomechanical resonator is analyzed. Modulating the incoming laser intensity at a suitably chosen frequency, the mechanically in ... [Appl. Phys. Lett. 94, 263104 (2009)] published Tue Jun 30, 2009.

Prediction of the formation of stable periodic self-interstitial cluster chains [(I),m=14] in Si under biaxial strain

Robert J. Bondi, Sangheon Lee, and Gyeong S. Hwang
Using density functional theory calculations, we examined the structure and stability of extendable self-interstitial cluster configurations (I,n=12,16) with four-atom periodicity in crystalline silicon under biaxial strain (4%<=epsilon<=4%) on Si(100). In the absence of strain, the ground state con ... [Appl. Phys. Lett. 94, 264101 (2009)] published Tue Jun 30, 2009.

Recovery time scales in a reversed-biased quantum dot absorber

Evgeny A. Viktorov, Thomas Erneux, Paul Mandel, Tomasz Piwonski, Gillian Madden et al.
The nonlinear recovery of quantum dot based reverse-biased waveguide absorbers is investigated both experimentally and analytically. We show that the recovery dynamics consists of a fast initial layer followed by a relatively slow decay. The fast recovery stage is completely determined by the intrad ... [Appl. Phys. Lett. 94, 263502 (2009)] published Tue Jun 30, 2009.

Morphology in semimagnetic PbMnSe nanocrystals: Thermal annealing effects

N. O. Dantas, R. S. Silva, F. Pelegrini, and G. E. Marques
Samples of PbMnSe nanocrystals were synthesized by fusion method and characterized by optical absorption, atomic force microscopy, x-ray diffraction, and electron paramagnetic resonance (EPR) techniques. Effects of Mn2 ion incorporation into PbSe nanocrystals are manifested by well resolved optical ... [Appl. Phys. Lett. 94, 263103 (2009)] published Tue Jun 30, 2009.

Plasmon-enhanced magneto-optical activity in ferromagnetic membranes

J. B. Gonzalez-Diaz, J. M. Garcia-Martin, A. Garcia-Martin, D. Navas, A. Asenjo et al.
Experimental and theoretical evidence of plasmon-enhanced Kerr rotation in purely ferromagnetic membranes with sufficiently small dimensions to be out of extraordinary optical transmission conditions (45 nm pore diameter, 90nm lattice constant), is reported in this work. It is shown that the spectra ... [Appl. Phys. Lett. 94, 263101 (2009)] published Tue Jun 30, 2009.

Orthogonal surface acoustic wave device based on langasite for simultaneous biosensing and biofouling removal

Reetu Singh, Subramanian K. R. S. Sankaranarayanan, and Venkat R. Bhethanabotla
We report a combined three-dimensional structural and fluid structure interaction finite element study of an orthogonal surface acoustic wave (SAW) device based on langasite (LGS). Our simulation results indicate that simultaneous sensing and nonspecifically bound protein removal can be achieved thr ... [Appl. Phys. Lett. 94, 263503 (2009)] published Tue Jun 30, 2009.

Enhancement of field emission of the ZnO film by the reduced work function and the increased conductivity via hydrogen plasma treatment

J. B. You, X. W. Zhang, P. F. Cai, J. J. Dong, Y. Gao et al.
The ZnO films deposited by magnetron sputtering were treated by H/O plasma. It is found that the field emission (FE) characteristics of the ZnO film are considerably improved after H-plasma treatment and slightly deteriorated after O-plasma treatment. The improvement of FE characteristics is attribu ... [Appl. Phys. Lett. 94, 262105 (2009)] published Tue Jun 30, 2009.

Silver halide single mode fibers for broadband middle infrared stellar interferometry

T. Lewi, A. Tsun, A. Katzir, J. Kaster, and F. Fuchs
We report the demonstration of silver halide single mode fibers at lambda=7.5 [mu]m. The fiber's modal behavior was tested at lambda=10.6 and lambda=7.5 [mu]m, using near field measurements. Single mode operation was observed for both wavelengths with propagation losses of ~16 and ~40 dB/m at lam ... [Appl. Phys. Lett. 94, 261105 (2009)] published Mon Jun 29, 2009.

Carbon nanotube photovoltaic device with asymmetrical contacts

Changxin Chen, Wei Zhang, Eric Siu-Wai Kong, and Yafei Zhang
A photovoltaic (PV) device based on high-work-function metal/single-walled carbon nanotube/low-work-function metal hybrid junction has been studied theoretically by the self-consistent nonequilibrium Green's function approach. The PV effect and power conversion efficiency (eta) of the device under l ... [Appl. Phys. Lett. 94, 263501 (2009)] published Mon Jun 29, 2009.

Well-aligned and suspended single-walled carbon nanotube film: Directed self-assembly, patterning, and characterization

Miao Lu, Min-Woo Jang, Greg Haugstad, Stephen A. Campbell, and Tianhong Cui
Self-assembly process, patterning, and characterization of well-aligned single-walled carbon nanotube (SWNT) films are presented in this letter. The dc current in an ac dielectrophoresis of an SWNT solution was measured and used to control the self-assembly process to get an oriented, compact SWNT f ... [Appl. Phys. Lett. 94, 261903 (2009)] published Mon Jun 29, 2009.

Temperature dependences of photoluminescence and electroluminescence spectra in light-emitting diodes

Lian Li, Ping Li, Yumei Wen, Jing Wen, and Yong Zhu
The temperature influence on the luminescence characteristics of light-emitting diodes (LEDs) is investigated to reveal the connection of photoluminescence (PL) with photon absorption and electroluminescence (EL) through current injection. By inspecting the PL and EL spectra at identical injection i ... [Appl. Phys. Lett. 94, 261103 (2009)] published Mon Jun 29, 2009.

Effects of phase transition on the hardness of shape memory alloys

Guozheng Kang and Wenyi Yan
Based on the dimensional analysis and finite element calculations, the effects of phase transition on the hardness of shape memory alloys were unveiled. It is shown that the hardness of shape memory alloys increases with the increase in the phase transition stress, the increase in the plastic yield ... [Appl. Phys. Lett. 94, 261906 (2009)] published Mon Jun 29, 2009.

Direct evidence for Sb as a Zn site impurity in ZnO

U. Wahl, J. G. Correia, T. Mendonca, and S. Decoster
The lattice location of ion implanted antimony in zinc oxide has been determined by means of beta emission channeling from the radioactive Sb isotope. Following 30 keV implantation of Sb into a single-crystalline ZnO sample to a fluence of 1 x 10 cm, the angular-dependent emission rate of beta part ... [Appl. Phys. Lett. 94, 261901 (2009)] published Mon Jun 29, 2009.

In situ passivation and blue luminescence of silicon clusters using a cluster beam/HO codeposition production method

A. Brewer and K. von Haeften
Si clusters are produced in a gas aggregation source and fly through ultrahigh vacuum onto a cold target where they are codeposited with water vapor. Melting of the ice yields immediately a suspension of nanoparticles that emits intense, nondegrading luminescence in the blue wavelength range. Spectr ... [Appl. Phys. Lett. 94, 261102 (2009)] published Mon Jun 29, 2009.

Probing misalignment in exchange biased systems: A dynamic approach

C. Le Graet, D. Spenato, S. P. Pogossian, D. T. Dekadjevi, and J. Ben Youssef
An experimental method based on ferromagnetic resonance is proposed to quantify the misalignment between ferromagnetic and antiferromagnetic easy axis in exchange biased systems. Our experimental study deals with NiFe/AlO and exchange biased NiFe/NiO bilayers. Performing ferromagnetic resonance stud ... [Appl. Phys. Lett. 94, 262502 (2009)] published Mon Jun 29, 2009.

Diamond Schottky-pn diode with high forward current density and fast switching operation

Toshiharu Makino, Satoshi Tanimoto, Yusuke Hayashi, Hiromitsu Kato, Norio Tokuda et al.
We fabricated a diamond diode, namely a Schottky-pn diode (SPND), which is composed of a fully depleted n-type active layer sandwiched between a highly doped p-type layer and a Schottky metal layer. The SPND has superior characteristics that overcome the weak points of both a Schottky barrier diode ... [Appl. Phys. Lett. 94, 262101 (2009)] published Mon Jun 29, 2009.

Publishers Note: All-optical delay line using semiconductor cavity solitons [Appl. Phys. Lett. 92, 011101 (2008)]

F. Pedaci, S. Barland, E. Caboche, P. Genevet, M. Giudici et al.
Abstract not available. [Appl. Phys. Lett. 94, 269902 (2009)] published Mon Jun 29, 2009.

Rectification of spin-bias-induced charge currents

Feng Zhai, Xiaofang Zhao, and H. Q. Xu
When a spin bias is applied to a two-terminal device, a charge current will be generated. We demonstrate the rectification of such a current by studying spin-dependent transport through a quantum point contact (QPC) modulated by a spin-orbit interaction. When the polarization orientation of the spin ... [Appl. Phys. Lett. 94, 262103 (2009)] published Mon Jun 29, 2009.

Design of electron wave filters in monolayer graphene by tunable transmission gap

Xi Chen and Jia-Wei Tao
We have investigated the transmission in monolayer graphene barrier at nonzero angle of incidence. Taking the influence of parallel wave vector into account, the transmission as the function of incidence energy has a gap due to the evanescent waves in two cases of Klein tunneling and classical motio ... [Appl. Phys. Lett. 94, 262102 (2009)] published Mon Jun 29, 2009.

200 mW type I GaSb-based laser diodes operating at 3 [mu]m: Role of waveguide width

Takashi Hosoda, Gela Kipshidze, Leon Shterengas, Sergey Suchalkin, and Gregory Belenky
Laser diodes based on AlInGaAsSb/InGaAsSb heterostructures with different waveguide widths were designed and fabricated. The decrease in the waveguide width from 1470 to 470 nm led to the improvement of the device performance. Lasers with 470 nm quinternary waveguides demonstrated 200 mW continuous ... [Appl. Phys. Lett. 94, 261104 (2009)] published Mon Jun 29, 2009.

Light polarization control in strain-engineered GaAsN/GaAsN:H heterostructures

R. Trotta, A. Polimeni, M. Capizzi, F. Martelli, S. Rubini et al.
The expansion of the GaAsN lattice following hydrogen incorporation is spatially patterned so as to generate an anisotropic stress in the sample growth plane. The resulting in-plane symmetry breaking determines an in-plane polarization dependence of the light emitted along the crystal growth directi ... [Appl. Phys. Lett. 94, 261905 (2009)] published Mon Jun 29, 2009.

Publishers Note: Carrier-induced ferromagnetism in GeMnTe epilayers with a Curie temperature up to 190 K [Appl. Phys. Lett. 93, 252502 (2008)]

Y. Fukuma, H. Asada, S. Miyawaki, T. Koyanagi, S. Senba et al.
Abstract not available. [Appl. Phys. Lett. 94, 269901 (2009)] published Mon Jun 29, 2009.

Ultrafast release and capture of carriers in InGaAs/GaAs quantum dots observed by time-resolved terahertz spectroscopy

H. P. Porte, P. Uhd Jepsen, N. Daghestani, E. U. Rafailov, and D. Turchinovich
We observe ultrafast release and capture of charge carriers in InGaAs/GaAs quantum dots in a room-temperature optical pump-terahertz probe experiment sensitive to the population dynamics of conducting states. In case of resonant excitation of the quantum dot ground state, the maximum conductivity is ... [Appl. Phys. Lett. 94, 262104 (2009)] published Mon Jun 29, 2009.

Enhanced exciton-phonon interactions in photoluminescence of ZnO nanopencils

Cheol Hyoun Ahn, Sanjay Kumar Mohanta, Nae Eung Lee, and Hyung Koun Cho
We report enhanced exciton-phonon interactions in the photoluminescence (PL) of ZnO nanopencils compared with ZnO nanorods grown on ZnO/Si templates by thermal evaporation. Although the low temperature (<100 K) PL spectra of ZnO nanorods and nanopencils were dominated by the strong donor-bound exci ... [Appl. Phys. Lett. 94, 261904 (2009)] published Mon Jun 29, 2009.

Surface tension of heavy water under high magnetic fields

Masaaki Iino and Yuu Fujimura
The surface tension of deuterium oxide-air interface was precisely measured under magnetic fields up to 10 T. The surface tension increased by 2.370.14 mN/m (3.300.19%) at 10 T. It was found that the surface tension increased linearly with an increase in the square of the magnetic field, the propor ... [Appl. Phys. Lett. 94, 261902 (2009)] published Mon Jun 29, 2009.

Vortex matching effect in engineered thin films of NbN

Ajay D. Thakur, Shuuichi Ooi, Subbaiah P. Chockalingam, John Jesudasan, Pratap Raychaudhuri et al.
We report robust vortex matching effects in antidot arrays fabricated on thin films of NbN. The near absence of hysteresis between field sweep directions indicates a negligible residual pinning in the host thin films. Owing to the very small coherence length of NbN thin films (xi<5 nm), the observa ... [Appl. Phys. Lett. 94, 262501 (2009)] published Mon Jun 29, 2009.

Nonlinear optical infrared microscopy with chemical specificity

Eun Seong Lee and Jae Yong Lee
We demonstrate a realization of nonlinear optical infrared microscopy that is capable of chemically specific imaging with high spatial resolution. It exploits the nonlinear refraction of the target material that is thermally induced by resonantly absorbed mid-infrared radiation and probed with a sho ... [Appl. Phys. Lett. 94, 261101 (2009)] published Mon Jun 29, 2009.

Model for electron mobility as a function of carrier concentration and strain in heavily doped strained silicon

N. S. Bennett, N. E. B. Cowern, and B. J. Sealy
Strain engineering plays a pivotal role in modern devices due to the advantages it offers in enhancing carrier mobility, [mu]. In addition to strain, epsilon, carrier concentration, N, also determines mobility and an understanding of the functional dependence [mu](N,epsilon) at various levels of str ... [Appl. Phys. Lett. 94, 252109 (2009)] published Fri Jun 26, 2009.

Effects of nitrogen incorporation on the interfacial layer between thermally grown dielectric films and SiC

S. A. Correa, C. Radtke, G. V. Soares, L. Miotti, I. J. R. Baumvol et al.
C-containing interlayers formed between the SiC substrate and dielectric films thermally grown in O, NO, and in O followed by annealing in NO were investigated. X-ray reflectometry and x-ray photoelectron spectroscopy were used to determine N and C incorporation in dielectric films and interlayers, ... [Appl. Phys. Lett. 94, 251909 (2009)] published Fri Jun 26, 2009.

Stripe domain structure in epitaxial (001) BiFeO thin films on orthorhombic TbScO substrate

C. M. Folkman, S. H. Baek, H. W. Jang, C. B. Eom, C. T. Nelson et al.
We have analyzed the ferroelastic and ferroelectric domain structure of high crystalline quality (001) BiFeO films on orthorhombic (110) TbScO substrates. Two domains were present in stripes separated by (010) vertical boundaries, with spontaneous polarizations in adjacent domains rotated by 109 deg ... [Appl. Phys. Lett. 94, 251911 (2009)] published Fri Jun 26, 2009.

Charge conduction mechanisms of atomic-layer-deposited ErO thin films

K. B. Jinesh, Y. Lamy, E. Tois, and W. F. A. Besling
The charge transport mechanism through atomic-layer-deposited erbium oxide thin films has been analyzed with current-voltage (I-V) measurements. At low electric field, i.e., below 3 MV/cm, the charge conduction through 10 nm thick ErO films is dominated by PooleFrenkel electron injection. However, F ... [Appl. Phys. Lett. 94, 252906 (2009)] published Fri Jun 26, 2009.

Nanorod epitaxial lateral overgrowth of a-plane GaN with low dislocation density

Shih-Chun Ling, Chu-Li Chao, Jun-Rong Chen, Po-Chun Liu, Tsung-Shine Ko et al.
The crystal quality of a-plane GaN films was improved by using epitaxial lateral overgrowth on a nanorod GaN template. The investigation of x-ray diffraction showed that the strain in a-plane GaN grown on r-plane sapphire could be mitigated. The average threading dislocation density estimated by tra ... [Appl. Phys. Lett. 94, 251912 (2009)] published Fri Jun 26, 2009.

Observation of whispering gallery modes in nonpolar m-plane GaN microdisks

Adele C. Tamboli, Mathew C. Schmidt, Asako Hirai, Steven P. DenBaars, and Evelyn L. Hu
We have fabricated nonpolar GaN/InGaN microdisks using band-gap selective photoelectrochemical etching. These microdisks have a smoother optical cavity than our previous c-plane microdisks, and they support whispering gallery modes with quality factors as high as 2000 after a focused ion beam treatm ... [Appl. Phys. Lett. 94, 251116 (2009)] published Fri Jun 26, 2009.

Structural and electrical properties of thin SrHfON films for high-k gate dielectric

Li-ping Feng and Zheng-tang Liu
Thin SrHfON films were prepared by reactive cosputtering of HfO and SrO targets in Ar/N ambient environment. Structural and electrical properties of the as-deposited and annealed SrHfON films used as gate dielectrics have been investigated. The SrHfON films have crystallization temperature higher th ... [Appl. Phys. Lett. 94, 252907 (2009)] published Fri Jun 26, 2009.

p-type doping efficiency of MoO in organic hole transport materials

S. Hamwi, J. Meyer, T. Winkler, T. Riedl, and W. Kowalsky
We report on the p-type doping efficiency of molybdenum trioxide (MoO) in the ambipolar organic charge transport material 4,4-Bis(carbazol-9-yl)-biphenyl (CBP). Kelvin probe analysis is used to study the work function with increasing thickness of doped CBP layers with varied MoO concentration deposi ... [Appl. Phys. Lett. 94, 253307 (2009)] published Fri Jun 26, 2009.

Optical transport of semiconductor nanowires on silicon nitride waveguides

D. Neel, S. Getin, P. Ferret, M. Rosina, J. M. Fedeli et al.
We investigate the behavior of silicon and ZnO nanowires in the evanescent field on the surface of a silicon nitride waveguide. The nanowires in aqueous solution are attracted to the waveguide by the gradient force and then propelled along the waveguide by the radiation pressure. Observed experiment ... [Appl. Phys. Lett. 94, 253115 (2009)] published Fri Jun 26, 2009.

Melting and crystallization of nanocrystalline silicon microwires through rapid self-heating

G. Bakan, A. Cywar, H. Silva, and A. Gokirmak
Nanocrystalline silicon microwires are self-heated through single, large amplitude, and microsecond voltage pulses. Scanning electron micrographs show very smooth wire surfaces after the voltage pulse compared to as-fabricated nanocrystalline texture. Voltage-pulse induced self-heating leads to sign ... [Appl. Phys. Lett. 94, 251910 (2009)] published Fri Jun 26, 2009.

Role of interface dipole in metal gate/high-k effective work function modulation by aluminum incorporation

Z. C. Yang, A. P. Huang, L. Yan, Z. S. Xiao, X. W. Zhang et al.
The interface dipole and its role in the effective work function (EWF) modulation by Al incorporation are investigated. Our study shows that the interface dipole located at the high-k/SiO interface causes an electrostatic potential difference across the metal/high-k interface, which significantly sh ... [Appl. Phys. Lett. 94, 252905 (2009)] published Fri Jun 26, 2009.

Pyrazine luminogens with free and locked phenyl rings: Understanding of restriction of intramolecular rotation as a cause for aggregation-induced emission

Anjun Qin, Jacky W. Y. Lam, Faisal Mahtab, Cathy K. W. Jim, Li Tang et al.
Nitrogen-containing heterocyclic pyrazine luminogens with free (1) and locked (2) phenyl rings were readily prepared in high yields. The propeller-shaped luminogen 1 shows aggregation-induced emission feature, whereas the disk-shaped chromophore 2 shows conventional aggregation-caused quenching effe ... [Appl. Phys. Lett. 94, 253308 (2009)] published Fri Jun 26, 2009.

Anomalous, hysteretic, transverse magnetoresistance in superconducting thin films with magnetic vortex arrays

J. E. Villegas, A. Sharoni, C.-P. Li, and Ivan K. Schuller
We have studied a superconducting/ferromagnetic hybrid system in which the normal to superconducting phase transition is controlled by the magnetic history. An anomalous transverse resistance appears at the phase transition, which shows magnetic hysteresis and a strong current dependence. We show th ... [Appl. Phys. Lett. 94, 252507 (2009)] published Fri Jun 26, 2009.

On the dynamical stability and metallic behavior of YH under pressure

J. S. de Almeida, D. Y. Kim, C. Ortiz, M. Klintenberg, and R. Ahuja
We report on the behavior of structural and electronic properties of yttrium trihydride under pressure using first principles calculations. We show that YH undergoes a structural transformation and its high pressure phase is dynamically stable under pressure since the peak at the imaginary frequenci ... [Appl. Phys. Lett. 94, 251913 (2009)] published Fri Jun 26, 2009.

The role of optical rectification in the generation of terahertz radiation from GaBiAs

K. Radhanpura, S. Hargreaves, R. A. Lewis, and M. Henini
We report on a detailed study of the emission of terahertz-frequency electromagnetic radiation from layers of GaBiAs (0<=y<0.04) grown by molecular beam epitaxy on (311)B and (001) GaAs substrates. We measure two orthogonally polarized components of the terahertz radiation emitted under excitation b ... [Appl. Phys. Lett. 94, 251115 (2009)] published Fri Jun 26, 2009.

Analytical solution of thickness variations in selective area growth by organometallic chemical vapor deposition

X. Liu and D. E. Aspnes
Using conformal mapping, we derive an analytic expression for the thickness d of a deposited film as a function of the distance r from a mask edge in selective area growth by organometallic chemical vapor deposition (OMCVD). Adjacent to the mask d~r, which is clearly different from the exponential d ... [Appl. Phys. Lett. 94, 253112 (2009)] published Thu Jun 25, 2009.

Phase-coherence and symmetry in four-terminal magnetotransport measurements on InN nanowires

R. Frielinghaus, S. Estevez Hernandez, R. Calarco, and Th. Schapers
Universal conductance fluctuations in n-type doped InN nanowires are investigated at temperatures down to 0.35 K. The nanowires were grown by molecular beam epitaxy. The effect of the contact resistance is eliminated by performing the measurements in a four-terminal configuration. We find that the d ... [Appl. Phys. Lett. 94, 252107 (2009)] published Thu Jun 25, 2009.

Effect of uniaxial pressure on metal-insulator transition in (SmNd)SrMnO single crystals

A. Murugeswari, P. Sarkar, S. Arumugam, N. Manivannan, P. Mandal et al.
We have investigated the effect of uniaxial pressure (P) on resistivity along the ab plane and c-axis in single crystals of (SmNd)SrMnO with y=0, 0.05, and 0.3. The application of pressure along the c-axis shifts the metal-insulator transition (MIT) to higher temperature, while MIT temperature decre ... [Appl. Phys. Lett. 94, 252506 (2009)] published Thu Jun 25, 2009.

Very high magnetocurrent in tris-(8-hydroxyquinoline) aluminum-based bipolar charge injection devices

Abd R. B. M. Yusoff, Wilson J. da Silva, Jose P. M. Serbena, Michelle S. Meruvia, and Ivo A. Hummelgen
Bipolar devices constructed using 60 nm thick tris-(8-hydroxyquinoline) aluminum (Alq) thin films sandwiched between a 200 nm thick sulfonated polyaniline hole-injection electrode and Al/Ca electron-injection electrode show very high (up to 10%) magnetocurrent values. True-hole-only and true-elect ... [Appl. Phys. Lett. 94, 253305 (2009)] published Thu Jun 25, 2009.

Nature of thermally stimulated acoustic emission from PbMgNbOPbTiO solid solutions

E. Dul'kin, E. Mojaev, M. Roth, I. P. Raevski, and S. A. Prosandeev
We discuss the nature of the thermally stimulated acoustic emission (AE) in single crystals of PbMgNbOPbTiO (PMN-PT). In particular, we derive an expression describing the efficiency of AE and we discuss in this connection AE from pure PMN. We have carried out original experiments revealing the depe ... [Appl. Phys. Lett. 94, 252904 (2009)] published Thu Jun 25, 2009.

Quantum cascade lasers with voltage defect of less than one longitudinal optical phonon energy

Matthew D. Escarra, Anthony J. Hoffman, Kale J. Franz, Scott S. Howard, Richard Cendejas et al.
Efficient use of applied voltage in quantum cascade (QC) lasers is a critical factor in achieving high wall-plug efficiency and low compliance voltage. We demonstrate a QC laser emitting at 4.2 [mu]m featuring a low voltage defect and short injector with only four quantum wells. Devices with a volt ... [Appl. Phys. Lett. 94, 251114 (2009)] published Thu Jun 25, 2009.

Temperature dependent charge-injection at the metal-organic semiconductor interface and density of states in pristine and doped pentacene

Claudio Vanoni, Thomas A. Jung, and Soichiro Tsujino
The authors study temperature dependent electrical transport in pristine and tetrafluorotetracyanoquinodimethane (FTCNQ)-doped pentacene to explore the physical mechanism of the doping-induced reduction in the contact resistance at the metal-organic semiconductor interface. It was found that the FTC ... [Appl. Phys. Lett. 94, 253306 (2009)] published Thu Jun 25, 2009.

A piezomagnetoelastic structure for broadband vibration energy harvesting

A. Erturk, J. Hoffmann, and D. J. Inman
This letter introduces a piezomagnetoelastic device for substantial enhancement of piezoelectric power generation in vibration energy harvesting. Electromechanical equations describing the nonlinear system are given along with theoretical simulations. Experimental performance of the piezomagnetoelas ... [Appl. Phys. Lett. 94, 254102 (2009)] published Thu Jun 25, 2009.

Polarity engineering in polycrystalline ZnO by inversion boundaries

Jong-Lo Park, Chan Park, Doh-Yeon Kim, Wook Jo, Chul-Jae Park et al.
Two distinctive polarity-engineered microstructures were obtained in polycrystalline ZnO ceramics by inducing two different types of inversion boundaries (IBs) inside individual grains to examine the effect of the different polarities on the varistor performances. The presence of head-to-head IBs in ... [Appl. Phys. Lett. 94, 252108 (2009)] published Thu Jun 25, 2009.

Composition and strain in SiGe/Si(001) nanorings revealed by combined x-ray and selective wet chemical etching methods

M. Stoffel, A. Malachias, A. Rastelli, T. H. Metzger, and O. G. Schmidt
The authors used x-ray diffraction to investigate strain and composition in SiGe nanorings formed during partial Si capping of self-assembled SiGe/Si(001) islands. The obtained results are corroborated with selective wet chemical etching experiments. Clear evidence is provided that rings are compose ... [Appl. Phys. Lett. 94, 253114 (2009)] published Thu Jun 25, 2009.

Potential measurement from a single lead ziroconate titanate nanofiber using a nanomanipulator

Xi Chen, Shiyou Xu, Nan Yao, Weihe Xu, and Yong Shi
Direct piezoelectric potential measurement of single lead ziroconate titanate (PZT) nanofiber under bending using a nanomanipulator inside a scanning electron microscope chamber was presented. The PZT nanofibers, with the diameter and length around 100 nm and 70100 [mu]m, respectively, were aligned ... [Appl. Phys. Lett. 94, 253113 (2009)] published Thu Jun 25, 2009.

Auxetic materials with large negative Poisson's ratios based on highly oriented carbon nanotube structures

Luzhuo Chen, Changhong Liu, Jiaping Wang, Wei Zhang, Chunhua Hu et al.
Auxetic materials with large negative Poisson's ratios are fabricated by highly oriented carbon nanotube structures. The Poisson's ratio can be obtained down to 0.50. Furthermore, negative Poisson's ratios can be maintained in the carbon nanotube/polymer composites when the nanotubes are embedded, w ... [Appl. Phys. Lett. 94, 253111 (2009)] published Thu Jun 25, 2009.

On the temperature dependence of point-defect-mediated luminescence in silicon

Daniel Recht, Federico Capasso, and Michael J. Aziz
We present a model of the temperature dependence of point-defect-mediated luminescence in silicon derived from basic kinetics and semiconductor physics and based on the kinetics of bound exciton formation. The model provides a good fit to data for W line electroluminescence and G line photoluminesce ... [Appl. Phys. Lett. 94, 251113 (2009)] published Thu Jun 25, 2009.

Categorization of resistive switching of metal-PrCaMnO-metal devices

Z. L. Liao, Z. Z. Wang, Y. Meng, Z. Y. Liu, P. Gao et al.
Resistive switching (RS) characteristics of a PrCaMnO (PCMO) film sandwiched between a Pt bottom electrode and top electrodes (TE) made of various metals are found to belong to two categories. Devices with TE made of Al, Ti, and Ta exhibit a large I-V hysteresis loop and bipolar RS, but those with T ... [Appl. Phys. Lett. 94, 253503 (2009)] published Wed Jun 24, 2009.

Symmetry-breaking-induced enhancement of visible light absorption in delafossite alloys

Muhammad N. Huda, Yanfa Yan, Aron Walsh, Su-Huai Wei, and Mowafak M. Al-Jassim
Through density functional theory calculations, we demonstrate that enhancement of optical absorption and optimization of the fundamental band gap for Cu delafossites can be achieved through alloying group IIIA and IIIB delafossites. These alloys significantly improved the flexibility in designing d ... [Appl. Phys. Lett. 94, 251907 (2009)] published Wed Jun 24, 2009.

Size-controlled one-dimensional monocrystalline BaTiO nanostructures

Ningzhong Bao, Liming Shen, Arunava Gupta, Alexander Tatarenko, Gopalan Srinivasan et al.
One-dimensional BaTiO nanostructures have been synthesized by a simple hydrothermal ion-exchange reaction using alkali-metal titanates as synthetic precursors. The BaTiO nanowires obtained from NaTiO nanowires have diameters of 5080 nm and lengths of up to 10 [mu]m. In contrast, BaTiO nanowires obt ... [Appl. Phys. Lett. 94, 253109 (2009)] published Wed Jun 24, 2009.

Surface-polarization-induced formation of amorphous foliaceous SiO helical nanobelts

L. Z. Liu, X. L. Wu, Z. Y. Zhang, T. H. Li, and Paul K. Chu
Amorphous foliaceous SiO helical nanobelts with equidistant alternating bright and dark stripes are synthesized using thermal evaporation. A very thin polar crystalline layer spontaneously formed on the nanobelt surface stabilizes the twist and the internal shear stress imbalance induces the periodi ... [Appl. Phys. Lett. 94, 253110 (2009)] published Wed Jun 24, 2009.

Pumping of atomic alkali lasers by photoexcitation of a resonance line blue satellite and alkali-rare gas excimer dissociation

J. D. Readle, C. J. Wagner, J. T. Verdeyen, T. M. Spinka, D. L. Carroll et al.
Photoassociation of alkali-rare gas atomic collision pairs provides an alternative approach to optically pumping atomic alkali lasers. Lasing on the 6 P-->6 S (D) transition of Cs has been observed when the blue satellite of the 6 P<--6 S (D) transition, peaking at ~837 nm for mixtures of Cs vapor, ... [Appl. Phys. Lett. 94, 251112 (2009)] published Wed Jun 24, 2009.

Grain boundary wetting and prewetting in Ni-doped Mo

Xiaomeng Shi and Jian Luo
Grain boundary (GB) wetting and prewetting in Ni-doped Mo are systematically evaluated via characterizing well-quenched specimens and thermodynamic modeling. In contrast to prior reports, the delta-NiMo phase does not wet Mo GBs in the solid state. In the solid-liquid two-phase region, the Ni-rich l ... [Appl. Phys. Lett. 94, 251908 (2009)] published Wed Jun 24, 2009.

Resistive dependence of magnetic properties in nonvolatile Ti/Mn:TiO/SrTiNbO/Ti memory device

S. X. Wu (吴曙翔), X. Y. Li (李新宇), X. J. Xing (邢祥军), P. Hu (胡苹), Y. P. Yu (余云鹏) et al.
We report the relationship of the magnetic properties of the Mn-doped TiO(Mn:TiO) thin film on SrTiTiO substrate to the different resistance states of the Ti/Mn:TiO/Nb:SrTiO/Ti device. Initially, the device showed paramagnetic behavior without applying voltage. When the device was switched to low re ... [Appl. Phys. Lett. 94, 253504 (2009)] published Wed Jun 24, 2009.

A two-photon pumped polyfluorene laser

Georgios Tsiminis, Arvydas Ruseckas, Ifor D. W. Samuel, and Graham A. Turnbull
A tunable two-photon pumped solid-state laser based on polyfluorene is reported. A detailed investigation of the two-photon absorption in polyfluorene for both nanosecond and femtosecond time regimes in solution, and solid-state allows the determination of the most favorable conditions for lasing. T ... [Appl. Phys. Lett. 94, 253304 (2009)] published Wed Jun 24, 2009.

An air-slotted nanoresonator relying on coupled high Q small V FabryPerot nanocavities

Kevin Foubert, Loic Lalouat, Benoit Cluzel, Emmanuel Picard, David Peyrade et al.
We study here the lateral evanescent coupling between photonic crystals cavities. The structure consists in two identical monomode FabryPerot nanocavities, integrated on silicon-on-insulator slot-waveguides (WG). Spectral and optical near field measurements were led and supported quantitatively by t ... [Appl. Phys. Lett. 94, 251111 (2009)] published Wed Jun 24, 2009.

High performance metal-insulator-metal capacitor using a SrTiO/ZrO bilayer

C. Jorel, C. Vallee, P. Gonon, E. Gourvest, C. Dubarry et al.
Future integration of metal-insulator-metal capacitors requires devices with high capacitance density and low quadratic voltage coefficient of capacitance (alpha). A major problem is that the increase in capacitance density is usually accompanied by increased voltage nonlinearities. By combining two ... [Appl. Phys. Lett. 94, 253502 (2009)] published Tue Jun 23, 2009.

Method to measure the viscosity of nanometer liquid films from the surface fluctuations

Zhaohui Yang, Chi-Hang Lam, Elaine DiMasi, Nathalie Bouet, Jean Jordan-Sweet et al.
We describe a method to measure the viscosity of polystyrene liquid films with thicknesses ~5 and ~80 nm spin-cast on oxide-coated silicon. In this method, temporal evolution of the film surface is monitored and modeled according to the dynamics of the surface capillary waves. Viscosities obtained ... [Appl. Phys. Lett. 94, 251906 (2009)] published Tue Jun 23, 2009.

Evaluation of the optical axis tilt of zinc oxide films via noncollinear second harmonic generation

F. A. Bovino, M. C. Larciprete, A. Belardini, and C. Sibilia
We investigated noncollinear second harmonic generation form zinc oxide films, grown on glass substrates by dual ion beam sputtering technique. At a fixed incidence angle, the generated signal is investigated by scanning the polarization state of both fundamental beams. We show that the map of the g ... [Appl. Phys. Lett. 94, 251109 (2009)] published Tue Jun 23, 2009.

Anomalous transport induced by sheath instability in Hall effect thrusters

Francesco Taccogna, Savino Longo, Mario Capitelli, and Ralf Schneider
It is well recognized to ascribe the anomalous cross-field conductivity inside Hall-effect thrusters to fluctuation-induced transport due to gradient-driven instabilities (Rayleigh or electron drift) and to electron-wall interaction (near-wall conductivity). In this letter, we have performed numeric ... [Appl. Phys. Lett. 94, 251502 (2009)] published Tue Jun 23, 2009.

Tunable nuclear polarization with external stationary fields in weakly coupled double quantum dots

Jesus Inarrea, Carlos Lopez-Monis, and Gloria Platero
Hyperfine interaction in double quantum dots releases spin blockade allowing the flux of electronic current. This interaction gives rise to a feedback mechanism between the spins of the electrons transported through the device and nuclei spins. In this letter, we analyze the role played by an extern ... [Appl. Phys. Lett. 94, 252106 (2009)] published Tue Jun 23, 2009.

Mechanical properties of superhard BC

P. Lazar and R. Podloucky
We apply density functional theory concept to investigate mechanical properties of the diamondlike compound BC. The cell volume and the bulk modulus are in very good agreement with the experiment, confirming the claimed crystal structure of BC. The cleavage properties revealed a very strong cohesion ... [Appl. Phys. Lett. 94, 251904 (2009)] published Tue Jun 23, 2009.

Terahertz time domain spectroscopy of phonon-depopulation based quantum cascade lasers

N. Jukam, S. S. Dhillon, D. Oustinov, J. Madeo, J. Tignon et al.
The gain and loss in a terahertz quantum cascade laser based on a longitudinal optical phonon depopulation scheme is studied using terahertz time domain spectroscopy. At laser threshold the gain is found to be clamped at 25 cm for a 1 mm long device and the full width at half maximum of the spectra ... [Appl. Phys. Lett. 94, 251108 (2009)] published Tue Jun 23, 2009.

Thick C:ZnPc bulk heterojunction solar cells with improved performance by film deposition on heated substrates

Steffen Pfuetzner, Jan Meiss, Annette Petrich, Moritz Riede, and Karl Leo
We study the influence of different substrate temperatures during the deposition of the ZnPc:C blend layer in bulk heterojunction organic solar cells. It is shown that substrate heating during evaporation leads to a significant improvement in the solar cell performance mainly due to an increase in p ... [Appl. Phys. Lett. 94, 253303 (2009)] published Tue Jun 23, 2009.

Reversible pyroelectric response in PbLa(ZrSnTi)O ceramics near its phase transition

Hongling Zhang, Xuefeng Chen, Fei Cao, Genshui Wang, Xianlin Dong et al.
Phase transition and pyroelectric behaviors of PbLa(ZrSnTi)O (PLZST) ceramics were investigated as functions of temperature and electric field. Pyroelectric coefficient about 160 x 10 C cm K is detected at the electric-field-induce ferroelectric (FE) to antiferroelectric phase transition for the po ... [Appl. Phys. Lett. 94, 252902 (2009)] published Tue Jun 23, 2009.

Tunable ultraviolet emission of ZnO quantum dots in transparent poly(methyl methacrylate)

Dazhi Sun and Hung-Jue Sue
We report experimental results on tuning ultraviolet (UV) emissions of colloidal ZnO quantum dots (QDs) with uniform size in poly(methyl methacrylate) (PMMA) through controlling their dispersion. Instead of using organic ligands, exfoliated nanoplatelets were utilized as an inorganic dispersant to a ... [Appl. Phys. Lett. 94, 253106 (2009)] published Tue Jun 23, 2009.

Single-crystal-like, c-axis oriented BaTiO thin films with high-performance on flexible metal templates for ferroelectric applications

Junsoo Shin, Amit Goyal, Stephen Jesse, and Dae Ho Kim
Epitaxial, c-axis oriented BaTiO thin films were deposited using pulsed laser ablation on flexible, polycrystalline Ni alloy tape with biaxially textured oxide buffer multilayers. The high quality of epitaxial BaTiO thin films with P4mm group symmetry was confirmed by x-ray diffraction. The microsco ... [Appl. Phys. Lett. 94, 252903 (2009)] published Tue Jun 23, 2009.

Simple method of light-shift suppression in optical pumping systems

B. H. McGuyer, Y.-Y. Jau, and W. Happer
We report a simple method to suppress the light shift in optical pumping systems. This method uses only frequency modulation of a radio frequency or microwave source, which is used to excite an atomic resonance, to simultaneously lock the source frequency to the atomic resonance and lock the pumping ... [Appl. Phys. Lett. 94, 251110 (2009)] published Tue Jun 23, 2009.

Robust room temperature persistent photoconductivity in polycrystalline indium oxide films

A. Dixit, Raghava P. Panguluri, C. Sudakar, P. Kharel, P. Thapa et al.
We have investigated the effects of UV irradiation on the electrical and optical properties of polycrystalline InO films. We found that UV illumination at a peak wavelength of 365 nm leads to a sharp drop in resistance and increase in carrier concentration. This highly conductive state persists for ... [Appl. Phys. Lett. 94, 252105 (2009)] published Tue Jun 23, 2009.

Erratum: Self-organized two-dimensional onions [Appl. Phys. Lett. 94, 113507 (2009)]

Shenqiang Ren, Robert M. Briber, and Manfred Wuttig
Abstract not available. [Appl. Phys. Lett. 94, 259901 (2009)] published Tue Jun 23, 2009.

Optimal control of the local electromagnetic response of nanostructured materials: Optimal detectors and quantum disguises.

Ilya Grigorenko and Herschel Rabitz
We consider the problem of optimization of an effective trapping potential in a nanostructure with a quasi-one-dimensional geometry. The optimization is performed to achieve certain target optical properties of the system. We formulate and solve the optimization problem for a nanostructure that serv ... [Appl. Phys. Lett. 94, 253107 (2009)] published Tue Jun 23, 2009.

Defect interactions in SnGe random alloys

A. Chroneos, C. Jiang, R. W. Grimes, U. Schwingenschlogl, and H. Bracht
SnGe alloys are candidates for buffer layers to match the lattices of III-V or II-VI compounds with Si or Ge for microelectronic or optoelectronic applications. In the present work electronic structure calculations are used to study relative energies of clusters formed between Sn atoms and lattice v ... [Appl. Phys. Lett. 94, 252104 (2009)] published Tue Jun 23, 2009.

Structure of liquid phase change material AgInSbTe from density functional/molecular dynamics simulations

J. Akola and R. O. Jones
The liquid phase of the AgInSbTe phase change material AgInSbTe has been studied using molecular dynamics/density functional simulations. The calculated structure factor and total pair distribution function agree very well with high-energy x-ray diffraction measurements. We find that: (a) there are ... [Appl. Phys. Lett. 94, 251905 (2009)] published Tue Jun 23, 2009.

Optical near-field probe with embedded gallium scattering center

D. V. Isakov, Y. Zhang, L. J. Balk, and J. C. H. Phang
An optical near-field probe is proposed in which gallium is embedded into the tip of a tapered optical glass fiber to form a scattering center. Gallium is embedded by implantation during the process of probe sharpening by a raster-scanned focused ion beam. Using quasielectrostatic approximation, it ... [Appl. Phys. Lett. 94, 253108 (2009)] published Tue Jun 23, 2009.

Fluorescence diffuse optical tomography using upconverting nanoparticles

Can T. Xu, Johan Axelsson, and Stefan Andersson-Engels
Fluorescence diffuse optical tomography (FDOT) can provide important information in biomedical studies. In this ill-posed problem, suppression of background tissue autofluorescence is of utmost importance. We report a method for autofluorescence-insensitive FDOT using nonlinear upconverting nanopart ... [Appl. Phys. Lett. 94, 251107 (2009)] published Tue Jun 23, 2009.

Subpicosecond quantum dot saturable absorber mode-locked semiconductor disk laser

Keith G. Wilcox, Mantas Butkus, Ian Farrer, David A. Ritchie, Anne Tropper et al.
We report the generation of subpicosecond pulses from a passively mode locked, optically pumped quantum well semiconductor disk laser using a quantum dot semiconductor saturable absorber mirror (SESAM). We obtained 870 fs pulses at a repetition rate of 895 MHz with average output power of 45 mW at 1 ... [Appl. Phys. Lett. 94, 251105 (2009)] published Mon Jun 22, 2009.

Specular electron scattering at single-crystal Cu(001) surfaces

J. S. Chawla and D. Gall
Epitaxial copper layers, 20 nm to 1.5-[mu]m-thick, were grown on MgO(001) by ultrahigh vacuum magnetron sputter deposition at 80 degrees C. In situ electrical resistivity measurements indicate partial specular scattering at the Cu vacuum interface with a FuchsSondheimer scattering parameter p=0.60. ... [Appl. Phys. Lett. 94, 252101 (2009)] published Mon Jun 22, 2009.

Metamaterials for optical security

A. Martinez, C. Garcia-Meca, R. Ortuno, F. J. Rodriguez-Fortuno, and J. Marti
In this letter we introduce the concept of optical security marks based on photonic metamaterials. We propose that a metamaterial with strong negative magnetic activity in the visible wavelength regime can be used to create a security mark that can be incorporated in any object to ensure its authent ... [Appl. Phys. Lett. 94, 251106 (2009)] published Mon Jun 22, 2009.

Notch insensitive fracture in nanoscale thin films

S. Kumar, M. A. Haque, and H. Gao
To study the effect of stress concentration at the nanoscale, we performed fracture experiments on single edge notched thin film specimens inside the transmission electron microscope. Even at about 4 GPa stress at the notch tip, the specimens failed far away from the notch at places with no apparent ... [Appl. Phys. Lett. 94, 253104 (2009)] published Mon Jun 22, 2009.

A standing-wave thermoacoustic engine with gas-liquid coupling oscillation

K. Tang (汤珂), T. Lei (雷田), T. Jin (金滔), X. G. Lin (林小钢), and Z. Z. Xu (徐振中)
A thermoacoustic engine usually uses either gas or liquid as the working fluid. However, an analysis based on acoustic-electric analogy indicates that gas-liquid coupling oscillation may lead to lower resonant frequency and larger pressure amplitude. A standing-wave thermoacoustic engine containing ... [Appl. Phys. Lett. 94, 254101 (2009)] published Mon Jun 22, 2009.

Magnetism of semiconductor-based magnetic tunnel junctions under electric field from first principles

Erjun Kan, Hongjun Xiang, Jinlong Yang, and Myung-Hwan Whangbo
Semiconductor magnetic tunnel junctions (MTJs), composed of diluted magnetic semiconductors (DMSs) sandwiching a semiconductor barrier, have potential applications in spintronics but their development has been slow due to the difficulty of controlling the magnetism of DMSs. In terms of density funct ... [Appl. Phys. Lett. 94, 252102 (2009)] published Mon Jun 22, 2009.

Origin of the phase transition of AlN, GaN, and ZnO nanowires

Yelong Wu, Guangde Chen, Honggang Ye, Youzhang Zhu, and Su-Huai Wei
The stabilities of AlN, GaN, and ZnO nanowires/nanorods with different structures and sizes are investigated using first-principles calculations. We found a structure transformation from the graphitelike phase to wurtzite phase as the diameter and length of the nanowire increases. We show that this ... [Appl. Phys. Lett. 94, 253101 (2009)] published Mon Jun 22, 2009.

Quantum electron transport through SrTiO: Effects of dopants on conductance channel

Zhongchang Wang, Susumu Tsukimoto, Mitsuhiro Saito, and Yuichi Ikuhara
Combining nonequilibrium Green's function technique with density functional theory, electronic structure and quantum transport of PtSrTiOPt heterostructures are investigated with special focus on effects of dopants. We find that intrinsically closed conductance channel in SrTiO opens after doping su ... [Appl. Phys. Lett. 94, 252103 (2009)] published Mon Jun 22, 2009.

Inversion in the temperature coefficient of the optical path length close to the glass transition temperature in tellurite glasses

S. M. Lima, L. H. C. Andrade, E. A. Falcao, A. Steimacher, N. G. C. Astrath et al.
In this study, thermal lens spectrometry was applied to determine the thermo-optical properties of fragile tellurite glasses as a function of temperature, close to the glass transition region. The results showed an inversion from positive to negative values in the temperature coefficient of the opti ... [Appl. Phys. Lett. 94, 251903 (2009)] published Mon Jun 22, 2009.

Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes

Seungjun Chung, Jae-Hyun Lee, Jaewook Jeong, Jang-Joo Kim, and Yongtaek Hong
We report substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes (OLEDs). Heat dissipation behavior of top-emission OLEDs fabricated on silicon, glass, and planarized stainless steel substrates was measured by using an infrared camera. Pea ... [Appl. Phys. Lett. 94, 253302 (2009)] published Mon Jun 22, 2009.

Valence electron energy-loss spectroscopy of nanoporous MgO

N. Jiang, D. Su, J. C. H. Spence, and A. Howie
This work reports experimental evidence for a redshift in the main peak in the valence electron energy loss spectrum of nanoporous MgO. An interpretation is given based on effective-medium response theory. We find that the main peak energy depends on the density of nanopores within the illuminated a ... [Appl. Phys. Lett. 94, 253105 (2009)] published Mon Jun 22, 2009.

Dual-function phase shifter for spin-wave logic applications

Ulf-Hendrik Hansen, Vladislav E. Demidov, and Sergej O. Demokritov
We have studied experimentally the linear and nonlinear control over the phase accumulation in a spin-wave phase shifter, which is a key element for construction of spin-wave logic devices. The linear control is realized by creation of a local inhomogeneity of the bias magnetic field, whereas the no ... [Appl. Phys. Lett. 94, 252502 (2009)] published Mon Jun 22, 2009.

Photoelectric field emission of electrons: Photon assisted tunneling

M. S. Sodha, A. Dixit, and S. Srivastava
This note is a discussion of the enhancement in electric field emission of electrons from a plane metallic surface on irradiation by light. The enhancement in the tunneling coefficient of an electron by absorption of a photon and the consequent increase in the field emission current has been evaluat ... [Appl. Phys. Lett. 94, 251501 (2009)] published Mon Jun 22, 2009.

Ultrafast all-optical light modulation in the near infrared region by phase sensitive polymer guided wave mode geometry containing porphyrin tapes

Ryuji Matsumoto, Toshihiko Nagamura, Naoki Aratani, Toshiaki Ikeda, and Atsuhiro Osuka
A phase sensitive detection was introduced into reflection type all-optical light modulation based on guided wave mode (GWM) geometry. A polymer film containing a copper porphyrin tape and a low refractive polymer film formed GWM at specific incident angle and wavelength. Sensitive changes of output ... [Appl. Phys. Lett. 94, 253301 (2009)] published Mon Jun 22, 2009.

Electron doping and magnetic moment formation in N- and C-doped MgO

A. Droghetti and S. Sanvito
The formation of the magnetic moment in C- and N-doped MgO is the result of a delicate interplay between Hund's coupling, hybridization, and JahnTeller distortion. The balance depends on a number of environmental variables including electron doping. We investigate such a dependence by self-interacti ... [Appl. Phys. Lett. 94, 252505 (2009)] published Mon Jun 22, 2009.

Direct measurement of transient electric fields induced by ultrafast pulsed laser irradiation of silicon

H. Park and J. M. Zuo
We use 30 kV electron pulses to probe transient electric fields above silicon surfaces by pump-probe. Electron beam deflection at 0.29 mm away from the sample surface on the order of 10 degrees is measured as a function of time delay and used to measure the local electric fields. The measured field ... [Appl. Phys. Lett. 94, 251103 (2009)] published Mon Jun 22, 2009.

Optical properties of GaSb-based type II quantum wells as the active region of midinfrared interband cascade lasers for gas sensing applications

M. Motyka, G. Sek, K. Ryczko, J. Misiewicz, T. Lehnhardt et al.
Photoreflectance and photoluminescence, supported by the energy level calculations in the eight-band kp model including strain, have been used to study the optical properties of GaSb/AlSb/InAs/InGaSb/AlSb/GaSb type II quantum wells (QWs). The broad emission wavelength tunability in the midinfrared r ... [Appl. Phys. Lett. 94, 251901 (2009)] published Mon Jun 22, 2009.

Excitation of propagating surface plasmons by a periodic nanoparticle array: Trade-off between particle-induced near-field excitation and damping

Amitabh Ghoshal and Pieter G. Kik
The excitation of propagating surface plasmons (SPs) on a silver-silica interface by an array of ellipsoidal silver nanoparticles is investigated using numerical simulations as a function of particle volume for three different nanoparticle aspect ratios with representative resonance frequencies. We ... [Appl. Phys. Lett. 94, 251102 (2009)] published Mon Jun 22, 2009.

Exchange bias in zinc-blende CrTeMnTe bilayer

J. F. Bi, H. Lu, M. G. Sreenivasan, and K. L. Teo
We have studied the exchange bias at the ferromagnetic (FM)/antiferromagnetic interface in the zinc-blende transition-metal chalcogenides, CrTe (5 nm)/MnTe(40 nm) bilayer grown on GaAs (100) substrate by molecular-beam epitaxy. A negative exchange bias shift in the hysteresis loop is observed when t ... [Appl. Phys. Lett. 94, 252504 (2009)] published Mon Jun 22, 2009.

Electrochemical growth of n-ZnO onto the p-type GaN substrate: p-n heterojunction characteristics

H. Asil, Emre Gur, K. Cinar, and C. Coskun
n-ZnO thin films were deposited electrochemically onto the p-GaN/AlO substrate in order to form hetero p-n junction. X-ray diffraction measurement has been showed clearly (0002) c-axis orientation of grown ZnO thin film. Absorption measurements were carried out before and after growth process indica ... [Appl. Phys. Lett. 94, 253501 (2009)] published Mon Jun 22, 2009.

Local opening of a large bandgap in metallic single-walled carbon nanotubes induced by tunnel injection of low-energy electrons

Kenta Yamada, Hiroaki Sato, Tetsuya Komaguchi, Yutaka Mera, and Koji Maeda
Probing with a tip of scanning tunneling microscopy (STM) of metallic single-walled carbon nanotubes (SWCNT) was found to induce defects in the tubes. The primary defect formation by probing was enhanced with a rate proportional to tunnel-injected electron current above a sample-bias threshold of ar ... [Appl. Phys. Lett. 94, 253103 (2009)] published Mon Jun 22, 2009.

Synthesis and magnetic properties of Al doped ZnMnO powers

Xiang Li, Zhou Yu, Xue Long, Pengtin Lin, Xingwang Cheng et al.
Chemical method was employed to synthesize Mn and Al codoped ZnO, namely, ZnMnAlO with the nominal composition of x=0, 0.005, and 0.02. Structural, optical, and magnetic properties of the produced samples were studied. The results indicated that introduce Al as additional dopants induces in an enhan ... [Appl. Phys. Lett. 94, 252501 (2009)] published Mon Jun 22, 2009.

Iterative optimization of plasmon resonant nanostructures

Prathamesh Pavaskar and Stephen B. Cronin
We perform finite difference time domain simulations of two-dimensional clusters of metal nanoparticles with incident planewave irradiation. An iterative optimization algorithm is used to determine the configuration of the nanoparticles that gives the maximum electric field intensity at the center o ... [Appl. Phys. Lett. 94, 253102 (2009)] published Mon Jun 22, 2009.

Femtosecond laser induced plasma diffraction gratings in air as photonic devices for high intensity laser applications

S. Suntsov, D. Abdollahpour, D. G. Papazoglou, and S. Tzortzakis
The creation of volume plasma density gratings in air by temporally overlapped high-intensity IR femtosecond laser pulses is demonstrated experimentally. Through the diffraction of various probe beams the plasma grating properties are recovered including its thickness and refractive index modulation ... [Appl. Phys. Lett. 94, 251104 (2009)] published Mon Jun 22, 2009.

Band alignments and improved leakage properties of (LaO)(SiO)/SiO/GaN stacks for high-temperature metal-oxide-semiconductor field-effect transistor applications

L. G. Gao, B. Xu, H. X. Guo, Y. D. Xia, J. Yin et al.
The band alignments of (LaO)(SiO)(LSO)/GaN and LSO/SiO/GaN gate dielectric stacks were investigated comparatively by using x-ray photoelectron spectroscopy. The valence band offsets for LSO/GaN stack and LSO/SiO/GaN stack are 0.88 and 1.69 eV, respectively, while the corresponding conduction band of ... [Appl. Phys. Lett. 94, 252901 (2009)] published Mon Jun 22, 2009.

Basins of attraction of tapping mode atomic force microscopy with capillary force interactions

Nastaran Hashemi and Reza Montazami
We perform a large number of simulations over a wide range of system parameters to approximate the basins of attraction of steady oscillating solutions. We find that the basins of attraction vary as a function of system parameters and initial conditions. For large equilibrium separations, the basin ... [Appl. Phys. Lett. 94, 251902 (2009)] published Mon Jun 22, 2009.

Enhancement in tunnel magnetoresistance effect by inserting CoFeB to the tunneling barrier interface in MnSi/MgO/CoCoFe magnetic tunnel junctions

S. Tsunegi, Y. Sakuraba, M. Oogane, Hiroshi Naganuma, K. Takanashi et al.
Tunnel magnetoresistance (TMR) effect was investigated in CoMnSi/CoFeB(02 nm)/MgO/CoFe magnetic tunnel junctions (MTJs). TMR ratio was enhanced by inserting a thin CoFeB layer at the CoMnSi/MgO interface. The MTJ with CoFeB thickness of 0.5 nm exhibited the highest TMR ratio. From the conductance-v ... [Appl. Phys. Lett. 94, 252503 (2009)] published Mon Jun 22, 2009.

Directional emission and universal far-field behavior from semiconductor lasers with limacon-shaped microcavity

Changling Yan, Qi Jie Wang, Laurent Diehl, Martina Hentschel, Jan Wiersig et al.
We report experimental demonstration of directional light emission from limacon-shaped microcavity semiconductor lasers. Quantum cascade lasers (QCLs) emitting at lambda[approximate]10 [mu]m are used as a model system. Both ray optics and wave simulations show that for deformations in the range 0.3 ... [Appl. Phys. Lett. 94, 251101 (2009)] published Mon Jun 22, 2009.