Applied Physics Letters: All Topics

The mechanism of the asymmetric SET and RESET speed of graphene oxide based flexible resistive switching memories

Lu-Hao Wang, Wen Yang, Qing-Qing Sun, Peng Zhou, Hong-Liang Lu et al.
Oxygen migration is reported as key factors of resistive switching in graphene oxide (GO) based memories by different groups. A flexible nonvolatile resistive switching memory based on GO was fabricated through a spin-coating process. The speed of the SET and RESET operations of the GO memories was ... [Appl. Phys. Lett. 100, 063509 (2012)] published Fri Feb 10, 2012.

Formation of an extended CoSi thin nanohexagons array coherently buried in silicon single crystal

Guinther Kellermann, Luciano A. Montoro, Lisandro J. Giovanetti, Paula C. dos Santos Claro, Liang Zhang et al.
A Co-doped silica film was deposited on the surface of a Si(100) wafer and isothermally annealed at 750 degrees C to form spherical Co nanoparticles embedded in the silica film and a few atomic layer thick CoSi nanoplatelets within the wafer. The structure, morphology, and spatial orientation of th ... [Appl. Phys. Lett. 100, 063116 (2012)] published Fri Feb 10, 2012.

Investigation of the band offsets caused by thin AlO layers in HfO based Si metal oxide semiconductor devices

Lior Kornblum, Boris Meyler, Catherine Cytermann, Svetlana Yofis, Joseph Salzman et al.
Ultrathin dielectric capping layers are a prominent route for threshold voltage control in advanced Si devices. In this work the position of an AlO layer inside a HfO-based stack is systematically varied and investigated following a low and a high temperature anneal. Electrical results are compared ... [Appl. Phys. Lett. 100, 062907 (2012)] published Fri Feb 10, 2012.

Resonantly enhanced optical nonlinearity in hybrid semiconductor quantum dot metal nanoparticle structures

Ming Fu, Kai Wang, Hua Long, Guang Yang, Peixiang Lu et al.
The optical nonlinearity of hybrid structures composed of CdTe quantum dots and periodical particle array of gold is studied using Z-scan method. The optical nonlinearity is dramatically affected by the interaction between exciton in CdTe quantum dots and surface plasmons in Au periodical particle a ... [Appl. Phys. Lett. 100, 063117 (2012)] published Fri Feb 10, 2012.

Investigation of the device instability feature caused by electron trapping in pentacene field effect transistors

Chang Bum Park
The phenomenon of device instability governed by electron trapping was investigated in pentacene field-effect transistors. We found that the threshold voltage shift (DeltaV) increases significantly when the device is exposed to photo-irradiation with the depletion gate bias. This effect reveals that ... [Appl. Phys. Lett. 100, 063306 (2012)] published Fri Feb 10, 2012.

Nonlinearity in the high-electric-field piezoelectricity of epitaxial BiFeO on SrTiO

Pice Chen, Rebecca J. Sichel-Tissot, Ji Young Jo, Ryan T. Smith, Seung-Hyub Baek et al.
The piezoelectricity of a multiferroic BiFeO thin film deviates from its low-field linear response in electric fields higher than 150 MV/m. Time-resolved synchrotron x-ray microdiffraction reveals a low-field piezoelectric coefficient of 55 pm/V and a steeper increase in strain at higher fields, wit ... [Appl. Phys. Lett. 100, 062906 (2012)] published Fri Feb 10, 2012.

Transparent conductive thin films of single-wall carbon nanotubes encapsulating dopant molecules

Naoki Kishi, Ikuma Miwa, Toshiya Okazaki, Takeshi Saito, Toshihisa Mizutani et al.
Transparent conductive thin films of single-wall carbon nanotubes (SWCNTs) doped with organic dopant molecules encapsulated inside the SWCNTs are reported. Doping with tetrafluorotetracyano-p-quinodimethane encapsulated within the SWCNTs improved the ratio of direct current to optical conductivity i ... [Appl. Phys. Lett. 100, 063121 (2012)] published Fri Feb 10, 2012.

Electronic rectification devices from carbon nanocones

Chen Ming, Zheng-Zhe Lin, Jun Zhuang, and Xi-Jing Ning
The electronic rectification effects of single wall carbon nanocones (SWCNCs) with cone angles 113 degrees , 60 degrees , and 39 degrees are shown by density functional theory calculation and non-equilibrium Green's functional method, and the 113 degrees cone owns the best rectification. Based on ... [Appl. Phys. Lett. 100, 063119 (2012)] published Fri Feb 10, 2012.

Epitaxial NiO gate dielectric on AlGaN/GaN heterostructures

Fabrizio Roccaforte, Giuseppe Greco, Patrick Fiorenza, Vito Raineri, Graziella Malandrino et al.
This letter reports on epitaxial nickel oxide (NiO) films grown by metal-organic chemichal vapor deposition on AlGaN/GaN heterostructures. The grown material was epitaxial, free from voids and exhibited a permittivity of 11.7, close to bulk NiO. This approach is advantageous with respect other metho ... [Appl. Phys. Lett. 100, 063511 (2012)] published Fri Feb 10, 2012.

Fabrication of disconnected three-dimensional silver nanostructures in a polymer matrix

Kevin Vora, SeungYeon Kang, Shobha Shukla, and Eric Mazur
We present a simple, one-step technique for direct-writing of a structured nanocomposite material with disconnected silver nanostructures in a polymer matrix. A nonlinear optical interaction between femtosecond laser pulses and a composite material creates silver structures that are embedded inside ... [Appl. Phys. Lett. 100, 063120 (2012)] published Fri Feb 10, 2012.

Bloch surface waves-controlled fluorescence emission: Coupling into nanometer-sized polymeric waveguides

Mirko Ballarini, Francesca Frascella, Emanuele Enrico, Pietro Mandracci, Natascia De Leo et al.
The lateral confinement of Bloch surface waves on a patterned multilayer is investigated by means of leakage radiation microscopy (LRM). Arrays of nanometric polymeric waveguides are fabricated on a proper silicon-nitride/silicon-oxide multilayer grown on a standard glass coverslip. By exploiting th ... [Appl. Phys. Lett. 100, 063305 (2012)] published Fri Feb 10, 2012.

Suppression of microwave rectification effects in electrically detected magnetic resonance measurements

C. C. Lo, F. R. Bradbury, A. M. Tyryshkin, C. D. Weis, J. Bokor et al.
Spin-dependent transport properties of micro- and nano-scale electronic devices are commonly studied by electrically detected magnetic resonance (EDMR). However, the applied microwave fields in EDMR experiments can induce large rectification effects and result in perturbations of the device bias con ... [Appl. Phys. Lett. 100, 063510 (2012)] published Fri Feb 10, 2012.

Half-harmonic Kelvin probe force microscopy with transfer function correction

Senli Guo, Sergei V. Kalinin, and Stephen Jesse
An approach for surface potential imaging based on half-harmonic band excitation (BE) in Kelvin probe force microscopy is demonstrated. Using linear and half-harmonic BE enables quantitative correction of the cantilever transfer function. Half-harmonic band excitation Kelvin probe force microscopy ( ... [Appl. Phys. Lett. 100, 063118 (2012)] published Fri Feb 10, 2012.

Energy harvesting in semiconductor-insulator-semiconductor junctions through excitation of surface plasmon polaritons

A. K. Pradhan, Terence Holloway, Rajeh Mundle, Hareesh Dondapati, and M. Bahoura
We have demonstrated a simple approach for developing a photovoltaic device consisting of semiconductor-insulator-semiconductor (SIS) heterojunction using surface plasmon polaritons (SPPs) generated in one of the semiconductors (Al:ZnO) and propagated through the dielectric barrier (SiO) to other (S ... [Appl. Phys. Lett. 100, 061127 (2012)] published Fri Feb 10, 2012.

Mechanically compliant grating reflectors for optomechanics

Utku Kemiktarak, Michael Metcalfe, Mathieu Durand, and John Lawall
We demonstrate micromechanical reflectors with a reflectivity as large as 99.4% and a mechanical quality factor Q as large as 7.8 x 10 for optomechanical applications. The reflectors are silicon nitride membranes patterned with sub-wavelength grating structures, obviating the need for the many die ... [Appl. Phys. Lett. 100, 061124 (2012)] published Fri Feb 10, 2012.

Charge density waves condensate as measure of charge order and disorder in EuSrMnO (x = 0.50, 0.58) manganites

Parul Pandey, Nilesh Awari, Rakesh Rana, Abhishek Singh, S. S. Prabhu et al.
We have explored the low-energy excitations in epitaxial thin films of EuSrMnO [x = 0.50: spin-glass with short range charge-order and x = 0.58: long range charge-order] using terahertz time-domain spectroscopy. A finite frequency peak structure in optical conductivity is observed at ~3.5 meV for bo ... [Appl. Phys. Lett. 100, 062408 (2012)] published Fri Feb 10, 2012.

Tantalum nitride superconducting single-photon detectors with low cut-off energy

A. Engel, A. Aeschbacher, K. Inderbitzin, A. Schilling, K. Il'in et al.
Materials with a small superconducting energy gap are expected to favor a high detection efficiency of low-energy photons in superconducting nanowire single-photon detectors. We developed a TaN detector with smaller gap and lower density of states at the Fermi energy than in comparable NbN devices, ... [Appl. Phys. Lett. 100, 062601 (2012)] published Fri Feb 10, 2012.

First-principles characterization of ferromagnetism in N-doped SrTiO and BaTiO

Kesong Yang, Ying Dai, and Baibiao Huang
The spin-polarization and magnetic coupling character of N-doped SrTiO (STO) and BaTiO (BTO) are studied through first-principles calculations. The substitutional N doping at O sites leads to a half-metallic property and produces a magnetic moment of 1.0 [mu]. The magnetic interaction between the ne ... [Appl. Phys. Lett. 100, 062409 (2012)] published Fri Feb 10, 2012.

Formation and structure of 360 and 540 degree domain walls in thin magnetic stripes

Youngman Jang, S. R. Bowden, Mark Mascaro, J. Unguris, and C. A. Ross
360 degrees , 540 degrees , and other complex transverse domain walls have been created in narrow cobalt wires connected to injection pads by cycling a magnetic field perpendicular to the wire length. The composite walls, formed by impingement of 180 degrees transverse walls of alternating chiralit ... [Appl. Phys. Lett. 100, 062407 (2012)] published Fri Feb 10, 2012.

Enhanced spontaneous emission from quantum dots in short photonic crystal waveguides

Thang Ba Hoang, Johannes Beetz, Leonardo Midolo, Matthias Skacel, Matthias Lermer et al.
We report a study of the quantum dot (QD) emission in short photonic crystal waveguides. We observe that the quantum dot photoluminescence intensity and decay rate are strongly enhanced when the emission energy is in resonance with Fabry-Perot (FP) cavity modes in the slow-light regime of the disper ... [Appl. Phys. Lett. 100, 061122 (2012)] published Fri Feb 10, 2012.

Virtual ghost imaging through turbulence and obscurants using Bessel beam illumination

Ronald E. Meyers, Keith S. Deacon, Arnold D. Tunick, and Yanhua Shih
We experimentally demonstrate a single sensor virtual ghost imaging (VGI) configuration that uses the physics of nearly diffraction free light sources to penetrate partially obscuring media or turbulent media and generate images of remote opaque objects. Randomly displaced nearly diffraction free Be ... [Appl. Phys. Lett. 100, 061126 (2012)] published Fri Feb 10, 2012.

Directional waveguide coupling from a wavelength-scale deformed microdisk laser

Brandon Redding, Li Ge, Glenn S. Solomon, and Hui Cao
We demonstrate uni-directional evanescent coupling of lasing emission from a wavelength-scale deformed microdisk to a waveguide. This is attributed to the Goos-Hanchen shift and Fresnel filtering effect that result in a spatial separation of the clockwise (CW) and counter-clockwise (CCW) propagating ... [Appl. Phys. Lett. 100, 061125 (2012)] published Fri Feb 10, 2012.

Periodically focused modes in chains of dielectric spheres

Arash Darafsheh and Vasily N. Astratov
We show that, theoretically, Brewster angle conditions for transverse magnetic polarized rays can be periodically reproduced in chains of spheres with index n = sqrt(3) giving rise to lossless periodically focused modes with 2D period, where D is the sphere diameter. Using ray tracing for a spherica ... [Appl. Phys. Lett. 100, 061123 (2012)] published Fri Feb 10, 2012.

Non-radiative complete surface acoustic wave bandgap for finite-depth holey phononic crystal in lithium niobate

Didit Yudistira, Yan Pennec, Bahram Djafari Rouhani, Samuel Dupont, and Vincent Laude
We demonstrate the existence of non-radiative complete surface acoustic wave (SAW) bandgaps for two-dimensional piezoelectric phononic crystals of holes. Holes of finite depth in a semi-infinite LiNbO substrate are specifically considered. SAW bandgaps are determined from the band structure calculat ... [Appl. Phys. Lett. 100, 061912 (2012)] published Fri Feb 10, 2012.

Electronic and magnetic properties of LaNiMnO and LaCoMnO with cationic ordering

Min Zhu, Yong Lin, Edward W. C. Lo, Qiong Wang, Zhengjie Zhao et al.
Employing first-principles electronic structure calculations, the electronic and magnetic properties of LaNiMnO and LaCoMnO with Ni/Mn and Co/Mn ordering in (001), (110), and (111) directions are investigated. The ground states of LaNiMnO and LaCoMnO are ferromagnetic semiconducting with alternative ... [Appl. Phys. Lett. 100, 062406 (2012)] published Fri Feb 10, 2012.

Understanding on the current-induced crystallization process and faster set write operation thereof in non-volatile phase change memory

Dae-Hwan Kang, Nan Young Kim, Hongsik Jeong, and Byung-ki Cheong
We experimentally demonstrate that the crystallization process of Ge-Sb-Te crystallites during the set operation in non-volatile phase change memory commences after threshold switching event. It is also shown that the nucleation and growth rates have opposite behaviors with the increase of set opera ... [Appl. Phys. Lett. 100, 063508 (2012)] published Thu Feb 9, 2012.

Wavelength-selective and diffuse emitter enhanced by magnetic polaritons for thermophotovoltaics

L. P. Wang and Z. M. Zhang
Both wavelength selectivity and directional insensitivity are highly desired in thermophotovoltaic applications. A concept of a magnetic-polariton-enhanced thermophotovoltaic emitter is presented. The predicted normal emittance from such a nanoengineered surface exceeds 0.8 in the wavelength region ... [Appl. Phys. Lett. 100, 063902 (2012)] published Thu Feb 9, 2012.

High mobility thin film transistors with indium oxide/gallium oxide bi-layer structures

S.-L. Wang, J.-W. Yu, P.-C. Yeh, H.-W. Kuo, L.-H. Peng et al.
We investigate the transport properties of thin-film transistors using indium oxide (InO)/gallium oxide (GaO) bi-layer stacks as the channel material. At low gate bias, we observe the transistor field-effect mobility increases with the film resistivity to [mu] = 51.3 cm/Vs and ON/OFF current ratio t ... [Appl. Phys. Lett. 100, 063506 (2012)] published Thu Feb 9, 2012.

Atomic layer deposited (TiO)(AlO)/InGaAs gate stacks for III-V based metal-oxide-semiconductor field-effect transistor applications

C. Mahata, S. Mallik, T. Das, C. K. Maiti, G. K. Dalapati et al.
Atomic layer deposited (ALD) (TiO)(AlO)(TiAlO) alloy gate dielectrics on InGaAs/InP substrates are shown to produce high quality interfaces between TiAlO and InGaAs. The surface morphology and interfacial reaction of nanolaminate ALD TiAlO on InGaAs are studied using atomic force microscopy and x-ra ... [Appl. Phys. Lett. 100, 062905 (2012)] published Thu Feb 9, 2012.

Electronic structures of an epitaxial graphene monolayer on SiC(0001) after metal intercalation (metal = Al, Ag, Au, Pt, and Pd): A first-principles study

Chia-Hsiu Hsu, Wen-Huan Lin, Vidvuds Ozolins, and Feng-Chuan Chuang
The atomic structures and electronic properties of metal-intercalated (metal = Al, Ag, Au, Pt, and Pd) graphene monolayers on SiC(0001) were investigated using first-principles calculations. The unique Dirac cone of graphene near the K point reappeared as the graphite layer was intercalated by these ... [Appl. Phys. Lett. 100, 063115 (2012)] published Thu Feb 9, 2012.

Cellular and molecular responses of Neurospora crassa to non-thermal plasma at atmospheric pressure

Gyungsoon Park, Young H. Ryu, Young J. Hong, Eun H. Choi, and Han S. Uhm
Filamentous fungi have been rarely explored in terms of plasma treatments. This letter presents the cellular and molecular responses of the filamentous fungus Neurospora crassa to an argon plasma jet at atmospheric pressure. The viability and cell morphology of N. crassa spores exposed to plasma wer ... [Appl. Phys. Lett. 100, 063703 (2012)] published Thu Feb 9, 2012.

Electron gas dimensionality engineering in AlGaN/GaN high electron mobility transistors using polarization

Pil Sung Park, Digbijoy N. Nath, Sriram Krishnamoorthy, and Siddharth Rajan
We propose and demonstrate a two dimensional/three dimensional hybrid channel AlGaN/GaN high electron mobility transistor (HEMT) structure with a flat transconductance profile using polarization-induced channel engineering. A quasi three dimensional electron gas profile with 56 nm of vertical channe ... [Appl. Phys. Lett. 100, 063507 (2012)] published Thu Feb 9, 2012.

Erratum: Addendum: `A study of capacitance-voltage curve narrowing effect in capacitive microelectromechanical switches' [Appl. Phys. Lett. 93, 094101 (2008)] [Appl. Phys. Lett. 100, 029903 (2012)]

Zbigniew Olszewski, Ruth Houlihan, Conor O'Mahony, and Russell Duane
Abstract not available. [Appl. Phys. Lett. 100, 069903 (2012)] published Thu Feb 9, 2012.

Publisher's Note: Dependence of carbon nanotube field effect transistors performance on doping level of channel at different diameters: On/off current ratio [Appl. Phys. Lett. 99, 263104 (2011)]

Shaahin G. Shirazi and Sattar Mirzakuchaki
Abstract not available. [Appl. Phys. Lett. 100, 069901 (2012)] published Thu Feb 9, 2012.

Graphene induced tunability of the surface plasmon resonance

Jing Niu, Young Jun Shin, Youngbin Lee, Jong-Hyun Ahn, and Hyunsoo Yang
Tunability of the surface plasmon resonance wavelength is demonstrated by varying the thickness of AlO spacer layer inserted between the graphene and nanoparticles. By varying the spacer layer thickness from 0.3 to 1.8 nm, the resonance wavelength is shifted from 583 to 566 nm. The shift is due to a ... [Appl. Phys. Lett. 100, 061116 (2012)] published Thu Feb 9, 2012.

Nanostructure thermal conductivity prediction by Monte Carlo sampling of phonon free paths

Alan J. H. McGaughey and Ankit Jain
We propose a method by which the thermal conductivity of a nanostructure with arbitrary geometry can be predicted through Monte Carlo sampling of the free paths associated with phonon-phonon and phonon-boundary scattering. The required inputs are the nanostructure geometry and the bulk phonon freque ... [Appl. Phys. Lett. 100, 061911 (2012)] published Thu Feb 9, 2012.

Epitaxial growth and demonstration of hexagonal BN/AlGaN p-n junctions for deep ultraviolet photonics

S. Majety, J. Li, X. K. Cao, R. Dahal, B. N. Pantha et al.
Recent advances in epitaxial growth and demonstration of p-type conductivity in hexagonal boron nitride (hBN) epilayers represent an exceptional opportunity to revolutionize p-layer approach and overcome the intrinsic problem of low p-type conductivity in Al-rich AlGaN for deep ultraviolet (DUV) dev ... [Appl. Phys. Lett. 100, 061121 (2012)] published Thu Feb 9, 2012.

Surface plasmon resonance-enabled antibacterial digital versatile discs

Xuan Dou, Pei-Yu Chung, Peng Jiang, and Jianli Dai
We report the achievement of effective sterilization of exemplary bacteria including Escherichia coli and Geobacillus stearothermophilus spores on a digital versatile disc (DVD). The spiral arrangement of aluminum-covered pits generates strong surface plasmon resonance (SPR) absorption of near-infra ... [Appl. Phys. Lett. 100, 063702 (2012)] published Thu Feb 9, 2012.

Erratum: Unintentional doping induced splitting of G peak in bilayer graphene [Appl. Phys. Lett. 99, 233110 (2011)]

S. S. Lin, B. G. Chen, C. T. Pan, S. Hu, P. Tian et al.
Abstract not available. [Appl. Phys. Lett. 100, 069902 (2012)] published Thu Feb 9, 2012.

Single photon emission from InGaN/GaN quantum dots up to 50 K

Stefan Kremling, Christian Tessarek, Heiko Dartsch, Stephan Figge, Sven Hofling et al.
We have investigated the optical properties of single InGaN quantum dots (QDs) by means of microphotoluminescence ([mu]PL) spectroscopy. The QDs were grown on sapphire substrate using metal organic vapor phase epitaxy. Sharp and isolated single exciton emission lines in the blue spectral range were ... [Appl. Phys. Lett. 100, 061115 (2012)] published Thu Feb 9, 2012.

Spontaneous formation of quantum height manganese gallium islands and atomic chains on N-polar gallium nitride(000[overline [bold 1]])

Abhijit Chinchore, Kangkang Wang, Meng Shi, Yinghao Liu, and Arthur R. Smith
Deposition of manganese onto the gallium-rich, nitrogen-polar GaN(000[overline 1]) surface results in the formation of quantum-height island structures. Two unique island heights differing by one atomic layer are observed, including 0.93 nm high islands which are unstable against the formation of 1. ... [Appl. Phys. Lett. 100, 061602 (2012)] published Thu Feb 9, 2012.

Room temperature single photon emission from an epitaxially grown quantum dot

O. Fedorych, C. Kruse, A. Ruban, D. Hommel, G. Bacher et al.
Single photon emission from an epitaxially grown quantum dot at room temperature is presented. CdSe/ZnSSe quantum dots are embedded into MgS barriers, providing dominant radiative recombination up to 300 K. Under continuous wave optical excitation, the autocorrelation function g(t) exhibits a sharp ... [Appl. Phys. Lett. 100, 061114 (2012)] published Thu Feb 9, 2012.

InGaN light-emitting diodes with indium-tin-oxide sub-micron lenses patterned by nanosphere lithography

Q. Zhang, K. H. Li, and H. W. Choi
Close-packed micro-lenses with dimensions of the order of wavelength have been integrated onto the indium-tin-oxide (ITO) layer of GaN light-emitting diodes employing nanosphere lithography. The ITO lens arrays are transferred from a self-assembled silica nanosphere array by dry etching, leaving the ... [Appl. Phys. Lett. 100, 061120 (2012)] published Thu Feb 9, 2012.

Anomaly of film porosity dependence on deposition rate

Stephen P. Stagon, Hanchen Huang, J. Kevin Baldwin, and Amit Misra
This letter reports an anomaly of film porosity dependence on deposition rate during physical vapor deposition the porosity increases as deposition rate decreases. Using glancing angle deposition of Cu on SiO substrate, the authors show that the Cu film consists of well separated nanorods when the ... [Appl. Phys. Lett. 100, 061601 (2012)] published Thu Feb 9, 2012.

Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma

Thomas Cummins, Takamitsu Otsuka, Noboru Yugami, Weihua Jiang, Akira Endo et al.
We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 [mu]m laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency of 0.4% was observed within a 0.6% bandwidth. A Faraday cup observed ion yield and time of flight sig ... [Appl. Phys. Lett. 100, 061118 (2012)] published Thu Feb 9, 2012.

Resonant magnetic response of TiO microspheres at terahertz frequencies

H. Nemec, C. Kadlec, F. Kadlec, P. Kuzel, R. Yahiaoui et al.
Spray-drying technique is used to fabricate spherical microparticles out of dissolved TiO nanoparticles. We show both experimentally and through numerical calculations that the microspheres support a Mie resonance, leading to an effective magnetic response. For this purpose, nearly single layers of ... [Appl. Phys. Lett. 100, 061117 (2012)] published Thu Feb 9, 2012.

Manifestation of quantum disordered wave functions with weak localization from conical second harmonic generation in ferroelectric crystal

H. H. Yu, H. J. Zhang, Z. P. Wang, H. H. Xu, Y. C. Wang et al.
The spatial structure of two-dimensional quantum disordered wave functions with weak localization (WL) is experimentally observed using a calcium barium niobate CaBaNbO (CBN-28) ferroelectric crystal illuminated by a pulsed laser beam. Non-collinear phase-matching in CBN-28 produces conical second h ... [Appl. Phys. Lett. 100, 061119 (2012)] published Thu Feb 9, 2012.

Nanometer sized Ni-dot/Ag/Pt structure for high reflectance of p-type contact metal in InGaN light emitting diodes

Kyu Sang Kim, Myoung Gyun Suh, and S. N. Cho
The Ni-dot/Ag/Pt layer, where Ni-dot layer is formed of nanometer sized Ni dots, has been used to improve the reflectivity from the surface of p-type GaN in a light emitting diode (LED). Comparing with Ni/Ag/Pt layer, where Ni layer is a thin film, the Ni-dot/Ag/Pt structure shows significantly impr ... [Appl. Phys. Lett. 100, 061113 (2012)] published Thu Feb 9, 2012.

Energy band engineering and controlled p-type conductivity of CuAlO thin films by nonisovalent Cu-O alloying

Z. Q. Yao, B. He, L. Zhang, C. Q. Zhuang, T. W. Ng et al.
The electronic band structure and p-type conductivity of CuAlO films were modified via synergistic effects of energy band offset and partial substitution of less-dispersive Cu 3d with Cu 3d orbitals in the valence band maximum by alloying nonisovalent Cu-O with CuAlO host. The Cu-O/CuAlO alloying fi ... [Appl. Phys. Lett. 100, 062102 (2012)] published Thu Feb 9, 2012.

Local structure of nitrogen in N-doped amorphous and crystalline GeTe

Alexander V. Kolobov, Paul Fons, Berangere Hyot, Bernard Andre, Junji Tominaga et al.
The local structure around nitrogen species in N-doped GeTe has been investigated using (soft) x-ray absorption spectroscopy and high-resolution x-ray photoemission spectroscopy. The obtained results demonstrate that while in as-deposited amorphous GeTe nitrogen is predominantly bonded to Ge atoms, ... [Appl. Phys. Lett. 100, 061910 (2012)] published Thu Feb 9, 2012.

Characterization of cluster/monomer ratio in pulsed supersonic gas jets

X. Gao, X. Wang, B. Shim, A. V. Arefiev, R. Korzekwa et al.
We determine cluster mass fraction f(r,t) at position r within, and time t after firing, a pulsed supersonic gas jet by measuring femtosecond evolution of the jet's refractive index by single-shot frequency domain holography. A fs pump pulse singly ionizes monomers, while quasi-statically ionizing a ... [Appl. Phys. Lett. 100, 064101 (2012)] published Wed Feb 8, 2012.

Thermally stable, sub-nanometer equivalent oxide thickness gate stack for gate-first InGaAs metal-oxide-semiconductor field-effect-transistors

M. El Kazzi, L. Czornomaz, C. Rossel, C. Gerl, D. Caimi et al.
Metal-oxide-semiconductor (MOS) capacitors were fabricated by depositing composite 2 nm HfO/1 nm AlO/1 nm a-Si gate stacks on p-InGaAs/InP (001) substrates. Thanks to the presence of the AlO barrier layer, a minimum amount of the a-Si passivating layer is oxidized during the whole fabrication proces ... [Appl. Phys. Lett. 100, 063505 (2012)] published Wed Feb 8, 2012.

Highly piezoelectric biocompatible and soft composite fibers

J. Morvan, E. Buyuktanir, J. L. West, and A. Jakli
We report the fabrication of highly piezoelectric biocompatible soft fibers containing barium titanate ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crysta ... [Appl. Phys. Lett. 100, 063901 (2012)] published Wed Feb 8, 2012.

Plasma resonances in a microwave-driven microdischarge

J. Xue, R. S. Urdahl, and J. E. Cooley
This work investigates resonances in a capacitively coupled, low pressure krypton microdischarge operated at 2.5 GHz. A circuit model for the device, which has a length dimension of approximately 1 mm, calculates impedance values for a range of electron densities. The model results predict several p ... [Appl. Phys. Lett. 100, 064102 (2012)] published Wed Feb 8, 2012.

Development of tilted hexagonal platelet ZnO using atmospheric pressure chemical vapor deposition and investigation of its growth mechanism

Y. Z. Yoo, S. H. Kim, G. S. Yoon, E. H. Choi, J.-W. Park et al.
Large area ZnO films (25 x 25 cm) grown via atmospheric pressure chemical vapor deposition (APCVD) showed unique surface morphologies of tilted hexagonal platelets. In response to the tilt angle change from 50 degrees to 75 degrees , haze values increased from 7% to 25%, indicating that tilt angl ... [Appl. Phys. Lett. 100, 061909 (2012)] published Wed Feb 8, 2012.

Coexistence of bi-stable memory and mono-stable threshold resistance switching phenomena in amorphous NbO films

Jieun Bae, Inrok Hwang, Yuhyun Jeong, Sung-Oong Kang, Sahwan Hong et al.
Both bi-stable memory and mono-stable threshold switching are observed in amorphous NbO films. In addition, the transition between memory and threshold switching can be induced by changing external electrical stress. Raman spectroscopy and transmission electron microscope data show that the NbO film ... [Appl. Phys. Lett. 100, 062902 (2012)] published Wed Feb 8, 2012.

Enhancement of photoluminescence signal from ultrathin layers with silicon nanocrystals

S. A. Dyakov, D. M. Zhigunov, A. Hartel, M. Zacharias, T. S. Perova et al.
Using the model of oscillating dipoles, we simulated the photoluminescence intensity of a triple-layered structure where the silicon nanocrystals layer was enclosed by buffer and capping silicon dioxide layers. It was found that a structure with an optimized buffer layer thickness exhibited photolum ... [Appl. Phys. Lett. 100, 061908 (2012)] published Wed Feb 8, 2012.

Spectral reflectance switching of colloidal photonic crystal structure composed of positively charged TiO nanoparticles

HongShik Shim, Joohyun Lim, Chang Gyun Shin, Seog-Jin Jeon, Moon Gyu Han et al.
We report the tunable photonic crystal behavior of highly concentrated, mildly charged TiO nanoparticle colloids under external electric field. Reflectance intensity change at the certain photonic bandgap and its irreversible switching characteristics are observed and discussed. Through computer aid ... [Appl. Phys. Lett. 100, 063113 (2012)] published Wed Feb 8, 2012.

Fullerene acceptor for improving open-circuit voltage in inverted organic photovoltaic devices without accompanying decrease in short-circuit current density

Yutaka Matsuo, Junichi Hatano, Takayuki Kuwabara, and Kohshin Takahashi
A poly(3-hexylthiophene) (P3HT)-based inverted organic photovoltaic (OPV) device with a fullerene electron acceptor, (dimethyl(o-anisyl)silylmethyl)(dimethylphenylsilylmethyl)[60]fullerene (SIMEF2), exhibited 2.9% power conversion efficiency (PCE; J = 7.9 mA/cm, V = 0.66 V, and FF = 0.56) in the dev ... [Appl. Phys. Lett. 100, 063303 (2012)] published Wed Feb 8, 2012.

Horizontally aligned ZnO nanowire transistors using patterned graphene thin films

Hwansoo Kim, Ji-Hoon Park, Misook Suh, Joung Real Ahn, and Sanghyun Ju
Here we report the directed growth of ZnO nanowires on multilayer graphene films (MGFs) without the use of metal seed materials. The ZnO source substance was diffused onto the MGF surface, where nanowires tended to grow in the high surface energy sites. This property was exploited to fabricate top-g ... [Appl. Phys. Lett. 100, 063112 (2012)] published Wed Feb 8, 2012.

High-pressure phases of NaAlH from first principles

Xiang-Feng Zhou (周向锋), Xiao Dong (董校), Zhisheng Zhao (赵智胜), Artem R. Oganov, Yongjun Tian (田永君) et al.
High-pressure phases of NaAlH are predicted using the ab initio evolutionary algorithm. our first-principles calculations reveal that the low-pressure I4/a phase containing AlH tetrahedra transforms into the monoclinic P2/c phase at 3.8 GPa and then into the orthorhombic Ima2 phase at 20.5 GPa. The ... [Appl. Phys. Lett. 100, 061905 (2012)] published Wed Feb 8, 2012.

Symmetry-breaking diffraction and dynamic self-trapping in optically induced hexagonal photonic lattices

Sheng Liu, Yi Hu, Peng Zhang, Xuetao Gan, Cibo Lou et al.
We demonstrate both experimentally and numerically linear symmetry-breaking diffraction and nonlinear dynamic self-trapping of an optical beam in hexagonal photonic lattices. We show that a stripe multivortex beam undergoes asymmetric linear diffraction, but evolves into a moving self-trapped beam u ... [Appl. Phys. Lett. 100, 061907 (2012)] published Wed Feb 8, 2012.

Exchange effects on spin-dependent ac transport

Jin Lan, Wen-Quan Sui, and Xuean Zhao
Spin-dependent ac transport problem is studied with exchange effects. Spin-spin exchange interaction and charge-charge Coulomb interaction are included simultaneously to determine the landscape of internal potential and the spin-dependent ac conductance. Gauge invariance and charge conservation are ... [Appl. Phys. Lett. 100, 062405 (2012)] published Wed Feb 8, 2012.

Fabrication of nanoscale glass fibers by electrospinning

M. Praeger, E. Saleh, A. Vaughan, W. J. Stewart, and W. H. Loh
We report the experimental realization of glass nanofibers by electrospinning directly from a melt, demonstrating the viability of electrospinning fibers from non-polymer materials with high melting temperatures and higher surface tensions. The nanofiber material (BO) is molten on the tip of a gold ... [Appl. Phys. Lett. 100, 063114 (2012)] published Wed Feb 8, 2012.

High-strength titanium alloy nanopillars with stacking faults and enhanced plastic flow

Qian Yu, Suzhi Li, Andrew M. Minor, Jun Sun, and Evan Ma
Through ex situ and in situ compression and tension tests of micrometer- and submicrometer-sized single crystal hexagonal close packed (HCP) Ti alloy pillars oriented for prismatic slip, we have observed that smaller is stronger and the larger samples exhibit obvious strain bursts. However, for extr ... [Appl. Phys. Lett. 100, 063109 (2012)] published Wed Feb 8, 2012.

Efficient hybrid white polymer light-emitting devices with electroluminescence covered the entire visible range and reduced efficiency roll-off

Sujun Hu, Minrong Zhu, Qinghua Zou, Hongbin Wu, Chuluo Yang et al.
We report efficient hybrid white polymer light emitting devices (WPLEDs) fabricated via simple solution-proceeded process from a newly synthesized wide band-gap fluorene-co-dibenzothiophene-S,S-dioxide copolymer, which dually function as fluorescent blue emitter and host material for electrophosphor ... [Appl. Phys. Lett. 100, 063304 (2012)] published Wed Feb 8, 2012.

Crystal and electronic structures of CuS solar cell absorbers

Qiang Xu, Bing Huang, Yufeng Zhao, Yanfa Yan, Rommel Noufi et al.
The crystal and electronic band structures of CuS(1.25 < x <= 2) are systematically studied using the density-functional theory method. For CuS, all the three chalcocite phases, i.e., the low-chalcocite, the high-chalcocite, and the cubic-chalcocite phases have direct band gaps around 1.31.5 eV, wit ... [Appl. Phys. Lett. 100, 061906 (2012)] published Wed Feb 8, 2012.

Phase field simulations of stress controlling the vortex domain structures in ferroelectric nanosheets

W. J. Chen, Yue Zheng, and Biao Wang
Effect of stress loads on the vortex domain structures (VDSs) in ferroelectric nanosheet has been investigated. Results of phase field simulations show that the different vortex domain structures can form in free-standing nanosheet from random perturbations. Applying stress loads on nanosheet, it is ... [Appl. Phys. Lett. 100, 062901 (2012)] published Wed Feb 8, 2012.

Anisotropic magneto-resistance in a GaMnAs-based single impurity tunnel diode: A tight binding approach

M. O. Nestoklon, O. Krebs, H. Jaffres, S. Ruttala, J.-M. George et al.
Using an advanced tight-binding approach, we estimate the anisotropy of the tunnel transmission associated with the rotation of the 5/2 spin of a single Mn atom forming an acceptor state in GaAs and located near an AlGaAs tunnel barrier. Significant anisotropies in both in-plane and out-of-plane geo ... [Appl. Phys. Lett. 100, 062403 (2012)] published Wed Feb 8, 2012.

Effect of surface plasmon energy matching on the sensing capability of metallic nano-hole arrays

Mohamadreza Najiminaini, Fartash Vasefi, Bozena Kaminska, and Jeffrey J. L. Carson
We report on a nano-hole array structure with a single cavity beneath the perforated gold film. Structures were fabricated with a variety of cavity depths. The optical resonance of each structure as well as the surface plasmon (SP) energy matching between the top and bottom of the gold film were inv ... [Appl. Phys. Lett. 100, 063110 (2012)] published Wed Feb 8, 2012.

Near-infrared nano-spectroscopy of semiconductor quantum dots using a phase-change mask layer

N. Tsumori, M. Takahashi, R. Kubota, P. Regreny, M. Gendry et al.
We propose a technique that uses an optical mask layer of a phase-change material (PCM), which is used for rewritable optical recording media, to achieve highly sensitive near-field imaging spectroscopy of single semiconductor quantum constituents at optical telecommunication wavelengths. An amorpho ... [Appl. Phys. Lett. 100, 063111 (2012)] published Wed Feb 8, 2012.

Asymmetric switching behavior in perpendicularly magnetized spin-valve nanopillars due to the polarizer dipole field

D. B. Gopman, D. Bedau, S. Mangin, C. H. Lambert, E. E. Fullerton et al.
We report the free layer switching field distributions of spin-valve nanopillars with perpendicular magnetization. While the distributions are consistent with a thermal activation model, they show a strong asymmetry between the parallel to antiparallel and the reverse transition, with energy barrier ... [Appl. Phys. Lett. 100, 062404 (2012)] published Wed Feb 8, 2012.

Dynamic hysteresis of tetragonal ferroelectrics: The resonance of 90 degrees -domain switching

D. P. Chen and J.-M. Liu
The dynamic hysteresis of ferroelectric lattice with 90 degrees -domain structure in response to time-varying electric field of frequency omega and amplitude E is investigated using Monte Carlo simulation based on the Ginzburg-Landau phenomenological theory. A resonance mode of the polarization swit ... [Appl. Phys. Lett. 100, 062904 (2012)] published Wed Feb 8, 2012.

Ionic-liquid-induced ferroelectric polarization in poly(vinylidene fluoride) thin films

Feipeng Wang, Alexander Lack, Zailai Xie, Peter Frubing, Andreas Taubert et al.
Thin films of ferroelectric beta-phase poly(vinylidene fluoride) (PVDF) were spin-coated from a solution that contained small amounts of the ionic liquid (IL) 1-ethyl-3-methylimidazolium nitrate. A remanent polarization of 60 mC/m and a quasi-static pyroelectric coefficient of 19 [mu]C/mK at 30 deg ... [Appl. Phys. Lett. 100, 062903 (2012)] published Wed Feb 8, 2012.

Broadband ferromagnetic resonance spectroscopy of permalloy triangular nanorings

J. Ding, M. Kostylev, and A. O. Adeyeye
We investigate the spin dynamics in triangular shaped permalloy rings using broadband ferromagnetic resonance spectroscopy. Compared with circular rings, we observed multiple resonance frequency peaks, which are strongly dependent on the orientation of the applied magnetic field relative to the hori ... [Appl. Phys. Lett. 100, 062401 (2012)] published Tue Feb 7, 2012.

Highly tunable whispering gallery mode semiconductor lasers with controlled absorber

A. N. Baranov, G. Boissier, R. Teissier, A. M. Monakhov, V. V. Sherstnev et al.
Tunable semiconductor lasers with controlled absorber based on GaInAsSb/GaAlAsSb quantum well heterostructure was fabricated and experimentally studied. The emission wavelength of these lasers shifts from 2.24 to 2.28 [mu]m when the bias on the control contact decreases from the voltage equal to tha ... [Appl. Phys. Lett. 100, 061112 (2012)] published Tue Feb 7, 2012.

Deformable transparent all-carbon-nanotube transistors

Shinya Aikawa, Erik Einarsson, Theerapol Thurakitseree, Shohei Chiashi, Eiichi Nishikawa et al.
We fabricated polymer-laminated, transparent, all-carbon-nanotube field-effect transistors (CNT-FETs), making use of the flexible yet robust nature of single-walled carbon nanotubes (SWNTs). All components of the FET (active channel, electrodes, dielectric layer, and substrate) consist of carbon-bas ... [Appl. Phys. Lett. 100, 063502 (2012)] published Tue Feb 7, 2012.

Four-mode plasmonic structure based on a prism-grating anticrossing bandgap

R. Chulia-Jordan and D. Santamaria-Perez
We have developed a plasmonic structure based on an anticrossing bandgap prism-grating coupling technique. We observe that up to four surface plasmons can be excited simultaneously in this plasmonic structure. Initial experiments confirm that such a plasmonic structure can improve sensor performance ... [Appl. Phys. Lett. 100, 063301 (2012)] published Tue Feb 7, 2012.

Metal contact to graphene nanoribbon

Gyungseon Seol and Jing Guo
Metal to graphene nanoribbon (GNR) contact is explored by self-consistent numerical simulations. The Schottky barrier height of the GNR contact can be modulated by either the gate voltage or the workfunction of the metal contact. An Ohmic contact with multiple-subband injection can be achieved with ... [Appl. Phys. Lett. 100, 063108 (2012)] published Tue Feb 7, 2012.

Interplay of point defects, biaxial strain, and thermal conductivity in homoepitaxial SrTiO thin films

S. Wiedigen, T. Kramer, M. Feuchter, I. Knorr, N. Nee et al.
Separating out effects of point defects and lattice strain on thermal conductivity is essential for improvement of thermoelectric properties of SrTiO. We study relations between defects generated during deposition, induced lattice strain, and their impact on thermal conductivity kappa in homoepitaxi ... [Appl. Phys. Lett. 100, 061904 (2012)] published Tue Feb 7, 2012.

Dependence of negative differential resistance on electronic phase separation in unpatterned manganite films

J. F. Ding, K. X. Jin, Z. Zhang, and T. Wu
Here, we report that small but well-defined negative differential resistance (NDR) steps can be observed at critical voltages in unpatterned millimeter-scale manganite films of Pr(CaSr)MnO. We systematically investigate the magneto-transport properties of strained thin films grown on LaAlO and SrTiO ... [Appl. Phys. Lett. 100, 062402 (2012)] published Tue Feb 7, 2012.

Mixed self-assembled monolayer of molecules with dipolar and acceptor characterInfluence on hysteresis and threshold voltage in organic thin-film transistors

Abdesselam Jedaa, Michael Salinas, Christof M. Jager, Timothy Clark, Alexander Ebel et al.
In this report, we investigate the impact of the molecular dipole moment and redox active head groups (C) in pure and mixed self-assembled monolayers (SAMs), which serve as an ultra-thin hybrid dielectric layer in low-voltage operating organic thin-film transistors. We show that the dipole of the SA ... [Appl. Phys. Lett. 100, 063302 (2012)] published Tue Feb 7, 2012.

Waveguide-integrated near-infrared detector with self-assembled metal silicide nanoparticles embedded in a silicon p-n junction

Shiyang Zhu, H. S. Chu, G. Q. Lo, P. Bai, and D. L. Kwong
An all-silicon photodetector integrated in a silicon-on-insulator waveguide for the telecom regime is proposed. The device is based on internal photoemission from electrically floating metal silicide nanoparticles (NPs) embedded in the space charge region of a Si p-n junction. Numerical simulation i ... [Appl. Phys. Lett. 100, 061109 (2012)] published Tue Feb 7, 2012.

Tunable piezoresistance and noise in gate-all-around nanowire field-effect-transistor

Pushpapraj Singh, Woo-Tae Park, Jianmin Miao, Lichun Shao, Rama Krishna Kotlanka et al.
The piezoresistance and noise of n-type gate-all-around nanowire field-effect-transistor (NWFET) is investigated as a function of gate bias. With narrow gate bias span of 0.6 V near threshold region, the piezoresistive coefficient of NWFET enhances up to seven times from 29 x 10 Pa to 207 x 10 P ... [Appl. Phys. Lett. 100, 063106 (2012)] published Tue Feb 7, 2012.

Rectifying behaviors induced by BN-doping in trigonal graphene with zigzag edges

X. Q. Deng, Z. H. Zhang, G. P. Tang, Z. Q. Fan, M. Qiu et al.
Based on nonequilibrium Green's functions in combination with density-function theory, the transport properties of trigonal graphenes, with the vertex carbon atom substituted by one phosphorus or boron atom and bounded through a B-N pair, coupled to gold electrodes are investigated. The rectificatio ... [Appl. Phys. Lett. 100, 063107 (2012)] published Tue Feb 7, 2012.

ZnO nanorods-graphene hybrid structures for enhanced current spreading and light extraction in GaN-based light emitting diodes

Jung Min Lee, Jaeseok Yi, Won Woo Lee, Hae Yong Jeong, Taeil Jung et al.
One-dimensional and two-dimensional hybrid structures, composed of vertical ZnO nanorods grown on large-area graphene, are successfully integrated onto the GaN/InGaN light emitting diodes (LEDs). Compared with GaN LED without transparent conducting electrode, current injection and light emission inc ... [Appl. Phys. Lett. 100, 061107 (2012)] published Tue Feb 7, 2012.

Use of the radiofrequency-intermodulation distortion technique to investigate intrinsic nonlinearity at the electrode-electrolyte interface

Rohit Pande, Leiming Xie, Wanda Zagozdzon-Wosik, Krzysztof Nesteruk, and Jarek Wosik
We report on investigations of nonlinear radiofrequency responses of electrolytes with Na and Cl ions placed within gold electrodes of a capacitor. The sample was part of a frequency-adjustable inductance-capacitance-resistance (LCR) parallel resonant circuit, and measurements were carried out using ... [Appl. Phys. Lett. 100, 063701 (2012)] published Tue Feb 7, 2012.

Full band atomistic modeling of homo-junction InGaAs band-to-band tunneling diodes including band gap narrowing

Woo-Suhl Cho, Mathieu Luisier, Dheeraj Mohata, Suman Datta, David Pawlik et al.
A homo-junction InGaAs tunneling diode is investigated using full-band, atomistic quantum transport approach based on a tight-binding model (TB) and the non-equilibrium Green's function formalism. Band gap narrowing (BGN) is included in TB by altering its parameters using the Jain-Roulston model [S. ... [Appl. Phys. Lett. 100, 063504 (2012)] published Tue Feb 7, 2012.

Parabolic polarization splitting of Tamm states in a metal-organic microcavity

R. Bruckner, M. Sudzius, S. I. Hintschich, H. Frob, V. G. Lyssenko et al.
We observe hybrid states of cavity photons and Tamm plasmons in an organic microcavity with an incorporated thin silver layer of increasing thickness up to 40 nm. Via [mu]-photoluminescence spectroscopy, we investigate their angular dependence. At oblique angles, we observe a TE-TM polarization spli ... [Appl. Phys. Lett. 100, 062101 (2012)] published Tue Feb 7, 2012.

Fourier-transform photocurrent spectroscopy using a supercontinuum light source

Christian Petermann, Rene Beigang, and Peer Fischer
We demonstrate an implementation of frequency-encoded photocurrent spectroscopy using a super-continuum light source. The spectrally broad light is spatially dispersed and modulated with a special mechanical chopper design that permits a continuous wavelength-dependent modulation. After recombinatio ... [Appl. Phys. Lett. 100, 061108 (2012)] published Tue Feb 7, 2012.

Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations

Emanuele Francesco Pecora, Wei Zhang, A. Yu. Nikiforov, Lin Zhou, David J. Smith et al.
Deep-UV optical gain has been demonstrated in AlGaN/AlN multiple quantum wells under femtosecond optical pumping. Samples were grown by molecular beam epitaxy under a growth mode that introduces band structure potential fluctuations and high-density nanocluster-like features within the AlGaN wells. ... [Appl. Phys. Lett. 100, 061111 (2012)] published Tue Feb 7, 2012.

X-ray spatial frequency heterodyne imaging

Binbin Wu, Yanan Liu, Christoph Rose-Petruck, and Gerald J. Diebold
We derive an expression for the electric field at the image plane from the Kirchhoff-Fresnel integral for a grating in contact with an object in an x-ray, in-line imaging configuration that shows the grating to give a heterodyning effect. We also show how image contrast in a harmonic of the grating ... [Appl. Phys. Lett. 100, 061110 (2012)] published Tue Feb 7, 2012.

Superconducting low-inductance undulatory galvanometer microwave amplifier

D. Hover, Y.-F. Chen, G. J. Ribeill, S. Zhu, S. Sendelbach et al.
We describe a microwave amplifier based on the superconducting low-inductance undulatory galvanometer (SLUG). The SLUG is embedded in a microstrip resonator, and the signal current is injected directly into the device loop. Measurements at 30 mK show gains of 25 dB at 3 GHz and 15 dB at 9 GHz. Ampli ... [Appl. Phys. Lett. 100, 063503 (2012)] published Tue Feb 7, 2012.

Electrically driven nanopyramid green light emitting diode

S.-P. Chang, Y.-C. Chen, J.-K. Huang, Y.-J. Cheng, J.-R. Chang et al.
An electrically driven nanopyramid green light emitting diode (LED) was demonstrated. The nanopyramid arrays were fabricated from a GaN substrate by patterned nanopillar etch, pillar side wall passivation, and epitaxial regrowth. Multiple quantum wells were selectively grown on the facets of the nan ... [Appl. Phys. Lett. 100, 061106 (2012)] published Tue Feb 7, 2012.

Manganese dioxide modified silicon nanowires and their excellent catalysis in the decomposition of methylene blue

Weiwei Gao, Mingwang Shao, Li Yang, Shujuan Zhuo, Shiyong Ye et al.
A redox between hydrofluoric acid and ammonium fluoride-treated silicon nanowires and potassium permanganate solution was investigated. The results showed that MnO nanoparticles might grow on the surface of silicon nanowires, which was confirmed with the transmission electron microscope. These MnO m ... [Appl. Phys. Lett. 100, 063104 (2012)] published Mon Feb 6, 2012.

Elastomeric silicone substrates for terahertz fishnet metamaterials

I. E. Khodasevych, C. M. Shah, S. Sriram, M. Bhaskaran, W. Withayachumnankul et al.
In this work, we characterize the electromagnetic properties of polydimethylsiloxane (PDMS) and use this as a free-standing substrate for the realization of flexible fishnet metamaterials at terahertz frequencies. Across the 0.22.5 THz band, the refractive index and absorption coefficient of PDMS ar ... [Appl. Phys. Lett. 100, 061101 (2012)] published Mon Feb 6, 2012.

Terahertz magnetic field induced coherent spin precession in YFeO

Runze Zhou, Zuanming Jin, Gaofang Li, Guohong Ma, Zhenxiang Cheng et al.
We present the magnetic dipole transition at 0.299 THz excited by magnetic component of terahertz electromagnetic pulse in an antiferromagnetic YFeO crystal. The impulsive magnetic field of the terahertz pulse tilts the macroscopic magnetization, causing deviation from the equilibrium position, whic ... [Appl. Phys. Lett. 100, 061102 (2012)] published Mon Feb 6, 2012.

Spontaneous induction of the uniform lying helix alignment in bimesogenic liquid crystals for the flexoelectro-optic effect

Damian J. Gardiner, Stephen M. Morris, Philip J. W. Hands, Flynn Castles, Malik M. Qasim et al.
Using in-plane electric fields, the electrical induction of the uniform lying helix (ULH) alignment in chiral nematic liquid crystals is reported. This process permits spontaneous induction of the ULH alignment to give an in-plane optic axis, without the need for complex processing. Flexoelectro-opt ... [Appl. Phys. Lett. 100, 063501 (2012)] published Mon Feb 6, 2012.

Twin-Foucault imaging method

Ken Harada (原田研)
A method of Lorentz electron microscopy, which enables observation two Foucault images simultaneously by using an electron biprism instead of an objective aperture, was developed. The electron biprism is installed between two electron beams deflected by 180 degrees magnetic domains. Potential appli ... [Appl. Phys. Lett. 100, 061901 (2012)] published Mon Feb 6, 2012.

Nucleobase adsorbed at graphene devices: Enhance bio-sensorics

Bo Song, Gianaurelio Cuniberti, Stefano Sanvito, and Haiping Fang
Graphene as a good material for sensing single small molecules is hardly believed to identify bio-molecules via electrical currents. This is because bio-molecules tend to bind to graphene through non-covalent bonds, such as pi-pi stacking interaction, which is not customarily considered to induce a ... [Appl. Phys. Lett. 100, 063101 (2012)] published Mon Feb 6, 2012.

Entropy change linked to the magnetic field induced Morin transition in Hematite nanoparticles

J. M. Pastor, J. I. Perez-Landazabal, C. Gomez-Polo, V. Recarte, S. Larumbe et al.
The most stable form of iron oxide is Hematite (alpha-FeO), which has interesting electronic, catalytic, and magnetic properties showing size dependent characteristics. At room temperature, Hematite is weakly ferromagnetic with a rhombohedral corundum structure. Upon cooling, the structure undergoes ... [Appl. Phys. Lett. 100, 063102 (2012)] published Mon Feb 6, 2012.

Suppression of photoconductivity by magnetic field in epitaxial manganite thin films

E. J. Guo, L. Wang, H. B. Lu, H. Z. Guo, M. He et al.
The erasure of photoinduced resistance (PR) by the magnetic field was investigated in manganite films. The PR was significantly suppressed when a magnetic field was introduced at low temperature. The decrease (or increase) of PR with increment of magnetic field was observed in ferromagnetic (or para ... [Appl. Phys. Lett. 100, 061902 (2012)] published Mon Feb 6, 2012.

Oxygen vacancy segregation and space-charge effects in grain boundaries of dry and hydrated BaZrO

B. Joakim Nyman, Edit E. Helgee, and Goran Wahnstrom
A space-charge model is applied to describe the equilibrium effects of segregation of double-donor oxygen vacancies to grain boundaries in dry and wet acceptor-doped samples of the perovskite oxide BaZrO. The grain boundary (GB) core vacancy concentrations and electrostatic potential barriers result ... [Appl. Phys. Lett. 100, 061903 (2012)] published Mon Feb 6, 2012.

Thermal and structural dependence of the band gap of quantum dots measured by a transparent film heater

Ju Yeon Woo, Suraj Kumar Tripathy, Kyungnam Kim, and Chang-Soo Han
We report the temperature dependence of the optical absorption and emission spectra of quantum dots (QDs) for three different nanocrystal (NC) structures (CdSe core, CdSe/CdS core/shell, and CdSe/CdS/ZnS core/multishell) in the solid film state. For this, a transparent single-walled carbon nanotube ... [Appl. Phys. Lett. 100, 063105 (2012)] published Mon Feb 6, 2012.

Two-dimensional electrostatic lattices for indirect excitons

M. Remeika, M. M. Fogler, L. V. Butov, M. Hanson, and A. C. Gossard
We report on a method for the realization of two-dimensional electrostatic lattices for excitons using patterned interdigitated electrodes. Lattice structure is set by the electrode pattern and depth of the lattice potential is controlled by applied voltages. We demonstrate square, hexagonal, and ho ... [Appl. Phys. Lett. 100, 061103 (2012)] published Mon Feb 6, 2012.

Self-aligned lateral dual-gate suspended-body single-walled carbon nanotube field-effect transistors

Ji Cao and Adrian M. Ionescu
Self-aligned lateral dual-gate suspended-body single-walled carbon nanotube (CNT) field-effect transistors (CNFETs) have been demonstrated. A nano-precision assembly method using resist-assisted ac-dielectrophoresis is applied. Superior I-V characteristics controlled by two independent lateral gates ... [Appl. Phys. Lett. 100, 063103 (2012)] published Mon Feb 6, 2012.

Analysis of Gouy phase shift for optimizing terahertz air-biased-coherent-detection

Huanyu He and X.-C. Zhang
Terahertz (THz) air-biased-coherent-detection (ABCD) uses a local oscillator to enhance THz-wave detection sensitivity by mixing an optical field, a THz field, and a biased electric field (local oscillator) in air. The width of the electrodes providing the local oscillator, the longitudinal distribu ... [Appl. Phys. Lett. 100, 061105 (2012)] published Mon Feb 6, 2012.

Comment on Design of acoustic devices with isotropic material via conformal transformation [Appl. Phys. Lett. 97, 044101 (2010)]

Andrew N. Norris
Abstract not available. [Appl. Phys. Lett. 100, 066101 (2012)] published Mon Feb 6, 2012.

Ultraviolet electroluminescence from colloidal ZnO quantum dots in an all-inorganic multilayer light-emitting device

T. Omata, Y. Tani, S. Kobayashi, K. Takahashi, A. Miyanaga et al.
We report ultraviolet (UV) electroluminescence (EL) at 3.30 eV of colloidal ZnO quantum dots (QDs) in an inorganic multilayer thin-film EL device. The EL spectrum was identical to the photoluminescence spectrum of the source solution of ZnO QDs, and the emission is attributable to quantum confined e ... [Appl. Phys. Lett. 100, 061104 (2012)] published Mon Feb 6, 2012.

Response to Comment on `Design of acoustic devices with isotropic material via conformal transformation' [Appl. Phys. Lett. 100, 066101 (2012)]

Zhihai Xiang, Chunyu Ren, and Zhangzhi Cen
Abstract not available. [Appl. Phys. Lett. 100, 066102 (2012)] published Mon Feb 6, 2012.

Role of deep and shallow donor levels on n-type conductivity of hydrothermal ZnO

S. Brochen, C. Granier, G. Feuillet, and J. Pernot
The residual n-type conductivity of O-polar hydrothermally grown ZnO single crystals and the role of annealing on the transport properties are assessed by temperature dependent Hall measurements on a wide 20800 K temperature range. A deep level lying 250 meV below the conduction band is responsible ... [Appl. Phys. Lett. 100, 052115 (2012)] published Fri Feb 3, 2012.

Publisher's Note: Dramatic thermal conductivity reduction by nanostructures for large increase in thermoelectric figure-of-merit of FeSb [Appl. Phys. Lett. 99, 163101 (2011)]

Huaizhou Zhao, Mani Pokharel, Gaohua Zhu, Shuo Chen, Kevin Lukas et al.
Abstract not available. [Appl. Phys. Lett. 100, 059902 (2012)] published Fri Feb 3, 2012.

Suppressed indium diffusion and enhanced absorption in InGaAs/GaAsP stepped quantum well solar cell

Yu Wen, Yunpeng Wang, and Yoshiaki Nakano
A multiple stepped quantum well (MSQW) structure, in which GaAs step layers are sandwiched between strain-balanced InGaAs wells and GaAsP barriers, has been proposed and improvements in sub-GaAs-bandgap QE have been demonstrated. We have studied the effect of indium diffusion on the optical properti ... [Appl. Phys. Lett. 100, 053902 (2012)] published Fri Feb 3, 2012.

Correlations between the thermal vibrations of two cantilevers: Validation of deterministic analysis via the fluctuation-dissipation theorem

Christopher D. F. Honig, Milad Radiom, Brian A. Robbins, John Y. Walz, Mark R. Paul et al.
We validate a theoretical approach for analyzing correlations in the fluctuations of two cantilevers in terms of a deterministic model, using the fluctuation-dissipation theorem [M. R. Paul and M. C. Cross, Phys. Rev. Lett. 92, 235501 (2004)]. The validation has been made possible through measuremen ... [Appl. Phys. Lett. 100, 053121 (2012)] published Fri Feb 3, 2012.

Cross-linking of a poly(3,4-ethylene dioxythiophene):(polystyrene sulfonic acid) hole injection layer with a bis-azide salt and the effect of atmospheric processing conditions on device properties

Oliver Fenwick, Kate Oliver, and Franco Cacialli
We investigate the role of atmospheric conditions during processing when cross-linking a poly(3,4-ethylene dioxythiophene):(polystyrene sulfonic acid) hole injection layer with a bis-azide salt. In particular, we investigate nitrogen atmosphere and air, since there is a competing reaction of the cro ... [Appl. Phys. Lett. 100, 053309 (2012)] published Fri Feb 3, 2012.

Investigation of proximity effects in electron microscopy and lithography

M.-M. Walz, F. Vollnhals, F. Rietzler, M. Schirmer, H.-P. Steinruck et al.
A fundamental challenge in lithographic and microscopic techniques employing focused electron beams are so-called proximity effects due to unintended electron emission and scattering in the sample. Herein, we apply a method that allows for visualizing electron induced surface modifications on a SiN ... [Appl. Phys. Lett. 100, 053118 (2012)] published Fri Feb 3, 2012.

Effect of overgrowth temperature on the mid-infrared response of Ge/Si(001) quantum dots

A. I. Yakimov, A. A. Bloshkin, V. A. Timofeev, A. I. Nikiforov, and A. V. Dvurechenskii
Ge/Si quantum dots fabricated by molecular-beam epitaxy at 500 degrees C are overgrown with Si at different temperatures T, and their mid-infrared photoresponse is investigated. The photocurrent maximum shifts from 2.3 to 3.9 [mu]m with increasing T from 300 to 750 degrees C. The best performance ... [Appl. Phys. Lett. 100, 053507 (2012)] published Fri Feb 3, 2012.

Cumulative effects of electrode and dielectric surface modifications on pentacene-based transistors

Melanie Devynck, Pascal Tardy, Guillaume Wantz, Yohann Nicolas, Luc Vellutini et al.
Surface modifications of the dielectric and the metal of pentacene-based field effect transistors using self-assembled monolayer (SAM) were studied. First, a low interfacial trap density and pentacene 2D-growth were favored by the nonpolar and low surface energy of octadecyltrichlorosilane-based SAM ... [Appl. Phys. Lett. 100, 053308 (2012)] published Fri Feb 3, 2012.

Light-driven tunable dual-band plasmonic absorber using liquid-crystal-coated asymmetric nanodisk array

Yanhui Zhao, Qingzhen Hao, Yi Ma, Mengqian Lu, Bingxin Zhang et al.
We experimentally demonstrated a light-driven reconfigurable near perfect plasmonic absorber working at dual frequencies in infrared range. By employing nanodisks with different sizes in certain arrangement, near perfect absorption of incident electromagnetic waves can be achieved for different work ... [Appl. Phys. Lett. 100, 053119 (2012)] published Fri Feb 3, 2012.

Enhancement of critical heat flux in pool boiling using atomic layer deposition of alumina

Bo Feng, Keith Weaver, and G. P. Peterson
Alumina nano coatings on platinum (Pt) micro wires were fabricated using atomic layer deposition. During the pool boiling heat transfer, the critical heat flux (CHF) of Pt/Alumina in de-ionized water was found to have a two-fold enhancement compared to that of the same Pt bare wire. The CHF was show ... [Appl. Phys. Lett. 100, 053120 (2012)] published Fri Feb 3, 2012.

Anisotropic magnetoresistance and weak spin-orbital coupling in doped ZnO thin films

Yufeng Tian, Weinan Lin, and Tom Wu
Both out-of-plane and in-plane anisotropic magnetoresistance (AMR) of Cu-doped ZnO thin films with different crystalline orientations are studied. Comparative data of angular dependent AMR suggest that the out-of-plane AMR comes from the geometric effect, while the in-plane AMR can be attributed to ... [Appl. Phys. Lett. 100, 052408 (2012)] published Fri Feb 3, 2012.

Tuning the interlayer exchange coupling between single perpendicularly magnetized CoFeB layers

R. Lavrijsen, A. Fernandez-Pacheco, D. Petit, R. Mansell, J. H. Lee et al.
We experimentally study the tunability of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interlayer exchange coupling (IEC) in Pt/CoFeB/Pt/Ru/Pt/CoFeB/Pt stacks with perpendicular magnetic anisotropy (PMA). The perpendicular magnetization of a single Pt/CoFeB/Pt (at. %) shows full remanence and square hys ... [Appl. Phys. Lett. 100, 052411 (2012)] published Fri Feb 3, 2012.

Thermal conductivity and photoluminescence of light-emitting silicon nitride films

Amy Marconnet, Matt Panzer, Selcuk Yerci, Salvatore Minissale, X. Wang et al.
Silicon-rich and rare-earth-doped nitride materials are promising candidates for silicon-compatible photonic sources. This work investigates the thermal conductivity and photoluminescence (PL) of light emitting samples fabricated with a range of excess silicon concentrations and annealing temperatur ... [Appl. Phys. Lett. 100, 051908 (2012)] published Fri Feb 3, 2012.

Standoff detection via single-beam spectral notch filtered pulses

Adi Natan, Jonathan M. Levitt, Leigh Graham, Ori Katz, and Yaron Silberberg
We demonstrate single-beam coherent anti-Stokes Raman spectroscopy (CARS), for detecting and identifying traces of solids, including minute amounts of explosives, from a standoff distance (>50 m) using intense femtosecond pulses. Until now, single-beam CARS methods relied on pulse-shapers in order t ... [Appl. Phys. Lett. 100, 051111 (2012)] published Fri Feb 3, 2012.

Deep traps in nonpolar m-plane GaN grown by ammonia-based molecular beam epitaxy

Z. Zhang, C. A. Hurni, A. R. Arehart, J. Yang, R. C. Myers et al.
Deep level defects in nonpolar m-plane GaN grown by ammonia-based molecular beam epitaxy were characterized using deep level transient spectroscopy (DLTS) and deep level optical spectroscopy (DLOS) and compared with polar c-plane GaN that was grown simultaneously in the same growth run. Significant ... [Appl. Phys. Lett. 100, 052114 (2012)] published Fri Feb 3, 2012.

Multiferroic phase competitions in perovskite manganite thin films

M. H. Qin, Y. M. Tao, M. Zeng, X. S. Gao, S. J. Wu et al.
Based on the Mochizuki-Furukawa model, the cycloidal spin structures of orthorhombic RMnO manganite thin films on various magnetic substrates are simulated using Monte Carlo method. It is revealed that the long range cycloidal spin order can be modulated by the film thickness and substrate spin stru ... [Appl. Phys. Lett. 100, 052410 (2012)] published Fri Feb 3, 2012.

A transparent 90 degrees polarization rotator by combining chirality and electromagnetic wave tunneling

Mehmet Mutlu and Ekmel Ozbay
A three-layer chiral metamaterial is constructed by using two layers of four mutually rotated resonators and a subwavelength mesh sandwiched symmetrically between these layers. The resulting structure is an ultrathin, transparent, and polarization angle independent 90 degrees polarization rotator. ... [Appl. Phys. Lett. 100, 051909 (2012)] published Fri Feb 3, 2012.

Improvement of coercivity and thermal stability of anisotropic NdFeBNbGa powders by diffusion of Pr-Cu alloys

Zhong Lin, Jingzhi Han, Meiying Xing, Shunquan Liu, Rui Wu et al.
Highly anisotropic NdFeBNbGa powders from a self-organized rod-like disproportionation microstructure and room temperature magnetic properties of [mu]M = 1.4 T, H = 13 kOe, and (BH) = 41 MGOe are obtained by optimizing hydrogenation disproportionation desorption recombination (HDDR) process. Diffusi ... [Appl. Phys. Lett. 100, 052409 (2012)] published Fri Feb 3, 2012.

A quantum model for light emission performance of carbon nanotube field effect transistor

M. R. Aziziyan, V. Ahmadi, and N. Moghadam
We propose a full quantum model based on non-equilibrium Green function method to simulate short channel, ohmic-carbon nanotube field effect transistor as light emitter. We consider carrier annihilation using self-energy concept in non-ballistic regime, regarding current conservation. Using this mod ... [Appl. Phys. Lett. 100, 051113 (2012)] published Fri Feb 3, 2012.

Fabrication of flower-like silver nanostructure on the Al substrate for surface enhanced fluorescence

Jun Dong (董军), Hairong Zheng (郑海荣), Xiaoqing Yan, Yu Sun, and Zhenglong Zhang
Surface-enhanced fluorescence (SEF) substrates consisting of flower-like nanostructure of electromagnetically coupled silver dendrites on Al surface were manufactured by modified galvanic displacement process between Ag ion and Al at room temperature. Substrate enhancement efficiency, which was eval ... [Appl. Phys. Lett. 100, 051112 (2012)] published Fri Feb 3, 2012.

Strong interband transitions in InAs quantum dots solar cell

Jiang Wu, Y. F. M. Makableh, R. Vasan, M. O. Manasreh, B. Liang et al.
Solar cells fabricated from a stack of ten periods of InAs quantum dots sandwiched in a GaAs p-n junction were fabricated and tested. The 300 K photoresponse spectrum exhibits two strong peaks and several weak peaks related to band-to-band transitions within the quantum dots. A few of these peaks we ... [Appl. Phys. Lett. 100, 051907 (2012)] published Fri Feb 3, 2012.

High-efficiency thin-film InGaP/InGaAs/Ge tandem solar cells enabled by controlled spalling technology

D. Shahrjerdi, S. W. Bedell, C. Ebert, C. Bayram, B. Hekmatshoar et al.
In this letter, we demonstrate the effectiveness of the controlled spalling technology for producing high-efficiency (28.7%) thin-film InGaP/(In)GaAs/Ge tandem solar cells. The controlled spalling technique was employed to separate the as-grown solar cell structure from the host Ge wafer followed by ... [Appl. Phys. Lett. 100, 053901 (2012)] published Thu Feb 2, 2012.

Tailoring of electro-optical properties of ferroelectric liquid crystals by doping Pd nanoparticles

A. Kumar, G. Singh, T. Joshi, G. K. Rao, A. K. Singh et al.
We demonstrate here the tailoring of electro-optical properties of ferroelectric liquid crystals (FLCs) by doping different concentrations of Selenium Docosane (SD) capped palladium nanoparticles (PdNPs). The operating voltage is lowered by ~50% in doped FLC as compared to undoped one. The remarkabl ... [Appl. Phys. Lett. 100, 054102 (2012)] published Thu Feb 2, 2012.

Three-dimensional control of Tetrahymena pyriformis using artificial magnetotaxis

Dal Hyung Kim, Paul Seung Soo Kim, Anak Agung Julius, and Min Jun Kim
We demonstrate three-dimensional control with the eukaryotic cell Tetrahymena pyriformis (T. pyriformis) using two sets of Helmholtz coils for xy-plane motion and a single electromagnet for z-direction motion. T. pyriformis is modified to have artificial magnetotaxis with internalized magnetite. To ... [Appl. Phys. Lett. 100, 053702 (2012)] published Thu Feb 2, 2012.

The effect of growth temperature of GaAs nucleation layer on InAs/GaAs quantum dots monolithically grown on Ge substrates

T. Wang, A. Lee, F. Tutu, A. Seeds, H. Liu et al.
The effect of the growth temperature of the GaAs nucleation layer on the properties of 1.3-[mu]m InAs/GaAs quantum dots (QDs) monolithically grown on a Ge substrate is investigated by using transmission electron microscopy, etch pit density, and photoluminescence (PL) measurements. The photoluminesc ... [Appl. Phys. Lett. 100, 052113 (2012)] published Thu Feb 2, 2012.

Long range supercurrents in ferromagnetic CrO using a multilayer contact structure

M. S. Anwar, M. Veldhorst, A. Brinkman, and J. Aarts
We report measurements of long ranged supercurrents through ferromagnetic and fully spin-polarized CrO deposited on TiO substrates. In earlier work, we found supercurrents in films grown on sapphire but not on TiO. Here, we employed a special contact arrangement, consisting of a Ni/Cu sandwich betwe ... [Appl. Phys. Lett. 100, 052602 (2012)] published Thu Feb 2, 2012.

Dipolar ordering of random two-dimensional spin ensemble

Andrey V. Panov
We theoretically study the randomly positioned two-dimensional system of interacting magnetic dipoles representing the monolayer arrays of single-domain particles. It is showed the onset of the dipolar in-plane superferromagnetic ordering of Ising spins at the surface concentrations of nanoparticles ... [Appl. Phys. Lett. 100, 052406 (2012)] published Thu Feb 2, 2012.

Anisotropy and extremely high coercivity in weak ferromagnetic LuFeO

Wenka Zhu, Li Pi, Shun Tan, and Yuheng Zhang
The temperature dependence of the structural anisotropy of weak ferromagnetic LuFeO is investigated through the XRD spectra at different temperatures. The structural anisotropy decreases with heating, which is in agreement with the magnetization-temperature measurement. The magnetic hysteresis loops ... [Appl. Phys. Lett. 100, 052407 (2012)] published Thu Feb 2, 2012.

Angular distribution of field emitted electrons from vertically aligned carbon nanotube arrays

S. Iacobucci, M. Fratini, A. Rizzo, F. Scarinci, Y. Zhang et al.
Angular field emission (FE) properties of vertically aligned carbon nanotube arrays have been measured on samples grown by plasma enhanced chemical vapor deposition and characterized by scanning electron microscope and I-V measurements. These properties determine the angular divergence of electron b ... [Appl. Phys. Lett. 100, 053116 (2012)] published Thu Feb 2, 2012.

Negative differential spin conductance in doped zigzag graphene nanoribbons

Ting-Ting Wu, Xue-Feng Wang, Ming-Xing Zhai, Hua Liu, Liping Zhou et al.
The spin dependent charge transport in zigzag graphene nanoribbons (ZGNRs) has been investigated by the nonequilibrium Green's function method combined with the density functional theory at the local spin density approximation. The current versus voltage curve shows distinguished behaviors for symme ... [Appl. Phys. Lett. 100, 052112 (2012)] published Thu Feb 2, 2012.

Picosecond transient photoluminescence in high-density Si-nanodisk arrays fabricated using bio-nano-templates

Takayuki Kiba, Yoshiya Mizushima, Makoto Igarashi, Chi-Hsien Huang, Seiji Samukawa et al.
We study picosecond transient photoluminescence (PL) in Si-nanodisk (Si-ND) arrays fabricated using bio-nano-templates. The PL time profiles show multi-exponential decaying kinetics depending on the disk density. We attribute the fastest decaying component with a decay time of 40 ps observed only in ... [Appl. Phys. Lett. 100, 053117 (2012)] published Thu Feb 2, 2012.

Observation of conductivity type conversion in undoped ZnO films grown by pulsed laser deposition on silicon (100) substrates

Saeed Esmaili-Sardari, Andrew Berkovich, and Agis A. Iliadis
We report a conductivity type conversion of ZnO films from n to p-type for films grown on silicon (100) substrates by pulsed laser deposition under low constant oxygen overpressure. Conductivity conversion is attributed to a competition between donor and acceptor-like native defects correlating with ... [Appl. Phys. Lett. 100, 053505 (2012)] published Thu Feb 2, 2012.

Optimal parameters for morphology of bulk heterojunction solar cells from simulations

Junwei Xue, Tingjun Hou, and Youyong Li
We combine atomistic simulation with mesoscale simulation to predict the morphology of bulk heterojunction (BHJ) solar cells. We show that good morphology is formed for weight fraction of PCBM in the region of 0.410.62 for poly(3-hexylthiophene)/[6,6]-phenyl-C butyric acid methyl ester BHJ solar cel ... [Appl. Phys. Lett. 100, 053307 (2012)] published Thu Feb 2, 2012.

Pressure-induced changes in the dielectric response of polymer relaxors

B. Hilczer, M. Szafranski, and A. Hilczer
The effect of hydrostatic pressure on the dielectric response of P(VDF/TrFE)(50/50) irradiated with fast electrons has been studied. A non-linear upward shift of the glass transition temperature T and the Curie temperature T of the polymer relaxors was observed under pressure with the initial slope ... [Appl. Phys. Lett. 100, 052904 (2012)] published Thu Feb 2, 2012.

Field-effect devices utilizing LaAlO-SrTiO interfaces

B. Forg, C. Richter, and J. Mannhart
Using LaAlO-SrTiO bilayers, we have fabricated field-effect devices that utilize the two-dimensional electron liquid generated at the bilayers' n-type interfaces as drain-source channels and the LaAlO layers as gate dielectrics. With gate voltages well below 1 V, the devices are characterized by vol ... [Appl. Phys. Lett. 100, 053506 (2012)] published Thu Feb 2, 2012.

Temperature dependence of the intraexcitonic AC Stark effect in semiconductor quantum wells

M. Wagner, M. Teich, M. Helm, and D. Stehr
We have investigated the temperature-dependent, intraexcitonic AC Stark effect that manifests itself in a line splitting of the heavy-hole 1s exciton transition in a GaAs/AlGaAs multi quantum well when the 1s-2p intraexciton transition is driven by intense THz light. The observed wavelength-dependen ... [Appl. Phys. Lett. 100, 051109 (2012)] published Thu Feb 2, 2012.

Surface depletion mediated control of inter-sub-band absorption in GaAs/AlAs semiconductor quantum well systems

Walter R. Buchwald, Justin W. Cleary, and Joshua Hendrickson
The modification of quantum well inter-sub-band absorption properties due to surface depletion induced band bending is reported. Fourier transform infrared spectroscopy measurements of a GaAs/AlAs multiple quantum well system reveal a reduction in the characteristic absorption resonance in correlati ... [Appl. Phys. Lett. 100, 051110 (2012)] published Thu Feb 2, 2012.

Temperature dependent dynamics of ZnO nanoparticles probed by Raman scattering: A big divergence in the functional areas of nanoparticles and bulk materials

Harish Kumar Yadav, R. S. Katiyar, and Vinay Gupta
Temperature dependent Raman scattering of the E(low) and E(high) modes of ZnO nanoparticle powder samples has been investigated. The dynamics exhibited by the ZnO nanoparticles, the E modes, follow single crystal like behavior but with strong cubic or/and quadratic anharmonicity by supporting additi ... [Appl. Phys. Lett. 100, 051906 (2012)] published Thu Feb 2, 2012.

Magnetic shape memory effect in orbital-spin-coupled system MnVO

Y. Nii, N. Abe, K. Taniguchi, and T. Arima
Magnetic-field(H)-induced shape memory effect without temperature variation is demonstrated by a combination of H-sweep and H-rotation in an orbital-spin-coupled spinel-type insulating system MnVO. A rotation of the direction of a magnetic field of 5 T in the low-temperature tetragonal phase gives r ... [Appl. Phys. Lett. 100, 051905 (2012)] published Thu Feb 2, 2012.

Cation stoichiometry optimization of SrTiO (110) thin films with atomic precision in homogeneous molecular beam epitaxy

Zhiming Wang, Jiagui Feng, Yang Yang, Yuan Yao, Lin Gu et al.
We study the evolution of surface reconstructions on SrTiO (110) determined by cation concentration ratio and find it detectable by high energy electron diffraction (RHEED) even at high temperature up to 800 degrees C. The evaporation rate of Sr and Ti sources can be calibrated precisely by monitor ... [Appl. Phys. Lett. 100, 051602 (2012)] published Thu Feb 2, 2012.

Time-of-flight-photoelectron emission microscopy on plasmonic structures using attosecond extreme ultraviolet pulses

S. H. Chew (周淑芬), F. Sussmann, C. Spath, A. Wirth, J. Schmidt et al.
We report on the imaging of plasmonic structures by time-of-flight-photoemission electron microscopy (ToF-PEEM) in combination with extreme ultraviolet (XUV) attosecond pulses from a high harmonic generation source. Characterization of lithographically fabricated Au structures using these ultrashort ... [Appl. Phys. Lett. 100, 051904 (2012)] published Thu Feb 2, 2012.

Erratum: Conversion from unipolar to bipolar resistance switching by inserting TaO layer in Pt/TaO/Pt cells [Appl. Phys. Lett. 98, 183507 (2011)]

H. K. Yoo, S. B. Lee, J. S. Lee, S. H. Chang, M. J. Yoon et al.
Abstract not available. [Appl. Phys. Lett. 100, 059901 (2012)] published Wed Feb 1, 2012.

ZnS-nanocrystals/polypyrrole nanocomposite film based immunosensor

Sujeet K. Mishra, Renu Pasricha, Ashok M Biradar, and Rajesh
We report an electrochemically synthesized ZnS nanocrystals modified polypyrrole (PPy) nanocomposite film based immunosensor for the detection of C-reactive protein (alphaCRP). The ZnS-PPy composite film was characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and e ... [Appl. Phys. Lett. 100, 053701 (2012)] published Wed Feb 1, 2012.

Thermally induced secondary atomization of droplet in an acoustic field

Saptarshi Basu, Abhishek Saha, and Ranganathan Kumar
We study the thermal effects that lead to instability and break up in acoustically levitated vaporizing fuel droplets. For selective liquids, atomization occurs at the droplet equator under external heating. Short wavelength [Kelvin-Helmholtz (KH)] instability for diesel and bio-diesel droplets trig ... [Appl. Phys. Lett. 100, 054101 (2012)] published Wed Feb 1, 2012.

Effect of the graded electron blocking layer on the emission properties of GaN-based green light-emitting diodes

Ning Zhang, Zhe Liu, Tongbo Wei, Lian Zhang, Xuecheng Wei et al.
We report on the effect of a graded AlGaN electron blocking layer (GEBL) on the emission properties of InGaN/GaN multiple quantum wells light-emitting diode (LED). The adoption of GEBL in the LED enhances the electroluminescence intensity and reduces the wavelength blue-shift with increasing injecti ... [Appl. Phys. Lett. 100, 053504 (2012)] published Wed Feb 1, 2012.

Optical detection of melting point depression for silver nanoparticles via in situ real time spectroscopic ellipsometry

S. A. Little, T. Begou, R. W. Collins, and S. Marsillac
Silver nanoparticle films were deposited by sputtering at room temperature and were annealed while monitoring by real time spectroscopic ellipsometry (SE). The nanoparticle dielectric functions (0.75 eV6.5 eV) obtained by SE were modeled using Lorentz and generalized oscillators for the nanoparticle ... [Appl. Phys. Lett. 100, 051107 (2012)] published Wed Feb 1, 2012.

Understanding metal doping for organic electron transport layers

Alexander Mityashin, David Cheyns, Barry P. Rand, and Paul Heremans
This work concerns the physical mechanisms of metal n-doping in charge transport layers for optoelectronic devices, for which the doping level is constrained by transparency requirements so as to avoid parasitic absorption. Comparing various metal dopants, we claim that enhanced conductivity at low ... [Appl. Phys. Lett. 100, 053305 (2012)] published Wed Feb 1, 2012.

Correlation between superconductivity and structural properties under high pressure of iron pnictide superconductor CeYFeAsOF

M. Kanagaraj, S. Arumugam, Ravhi S. Kumar, N. R. Tamil Selvan, S. Esakki Muthu et al.
We report here the pressure dependence of the electrical resistivity and magnetic susceptibility of polycrystalline CeYFeAsOF superconductor in the temperature range 4 K to 300 K up to 8 GPa. In-situ high pressure-low temperature x-ray diffraction was performed at 8 K up to 32 GPa using synchrotron ... [Appl. Phys. Lett. 100, 052601 (2012)] published Wed Feb 1, 2012.

Electrical phase transition of poly(4,4[prime]-aminotriphenylene hexafluoroisopropylidenediphthalimide) by photogenerated charged carrier injection

Kyoung-Jae Lee, Dong Min Kim, Kyuwook Ihm, Moonhor Ree, Tai-Hee Kang et al.
We show a set-up of poly(4,4[prime]-aminotriphenylene hexafluoroisopropylidenediphthalimide) (6F-TPA PI)/Al sample in which holes are injected by photoelectron emission process instead of direct charge carrier injection via metal electrode. In this process, an irreversible electrical phase transitio ... [Appl. Phys. Lett. 100, 053306 (2012)] published Wed Feb 1, 2012.

Magnetostructural phase transitions and magnetocaloric effects in MnNiGeAl

Tapas Samanta, Igor Dubenko, Abdiel Quetz, Samuel Temple, Shane Stadler et al.
The thermomagnetic and magnetocaloric properties of the MnNiGeAl system have been investigated by magnetization and differential scanning calorimetry (DSC) measurements. The presence of first-order magnetostructural transitions (MSTs) from hexagonal ferromagnetic to orthorhombic antiferromagnetic ph ... [Appl. Phys. Lett. 100, 052404 (2012)] published Wed Feb 1, 2012.

Experimental generation of a radially polarized beam with controllable spatial coherence

Fei Wang, Yangjian Cai, Yiming Dong, and Olga Korotkova
We have experimentally generated a radially polarized (RP) beam with controllable state of spatial coherence by using a rotating ground-glass plate and a radial polarization converter. Furthermore, experimental and theoretical analysis of the focusing properties of a partially coherent RP beam is ca ... [Appl. Phys. Lett. 100, 051108 (2012)] published Wed Feb 1, 2012.

Influence of a transverse static magnetic field on the magnetic hyperthermia properties and high-frequency hysteresis loops of ferromagnetic FeCo nanoparticles

B. Mehdaoui, J. Carrey, M. Stadler, A. Cornejo, C. Nayral et al.
The influence of a transverse static magnetic field on the magnetic hyperthermia properties is studied on a system of large-losses ferromagnetic FeCo nanoparticles. The simultaneous measurement of the high-frequency hysteresis loops and of the temperature rise provides an interesting insight into th ... [Appl. Phys. Lett. 100, 052403 (2012)] published Wed Feb 1, 2012.

Boundary-enhanced momentum relaxation of longitudinal optical phonons in GaN

N. Ma, B. Shen, L. W. Lu, F. J. Xu, L. Guo et al.
The influence of the channel geometry on the high-field electron transport properties has been investigated in n-type GaN at room temperature. It is found that electrons in narrow channels drift much faster than those in wide channels. This discrepancy is attributed to the boundary-enhanced momentum ... [Appl. Phys. Lett. 100, 052109 (2012)] published Wed Feb 1, 2012.

Mapping the electronic properties of individual graphene grain boundaries

Levente Tapaszto, Peter Nemes-Incze, Gergely Dobrik, Kwon Jae Yoo, Chanyong Hwang et al.
Grain boundaries, the characteristic topological defects of chemical vapor deposition grown graphene samples, are expected to substantially alter the electronic properties of the unperturbed graphene lattice. However, there is very little experimental insight into the underlying mechanisms. Here, we ... [Appl. Phys. Lett. 100, 053114 (2012)] published Wed Feb 1, 2012.

All-metallic lateral spin valves using CoFe(GeGa) Heusler alloy with a large spin signal

Y. K. Takahashi, S. Kasai, S. Hirayama, S. Mitani, and K. Hono
A large spin signal (DeltaR) of 12.8 mOmega at room temperature is demonstrated in an all-metallic lateral spin valve (LSV) device comprising of ferromagnetic wire of a highly spin-polarized CoFe(GeGa) Heusler alloy and a Cu wire. From the results on multi-terminal LSV devices, the origin of the lar ... [Appl. Phys. Lett. 100, 052405 (2012)] published Wed Feb 1, 2012.

Electronic transport anisotropy of buckling graphene under uniaxial compressive strain: Ab initio study

Yang Xu, Haiyuan Gao, Huabin Chen, You Yuan, Kaicheng Zhu et al.
Electronic transport properties of graphene under uniaxial compressive strain are studied using ab initio calculations. With approximate thermal perturbation, buckling occurs when strain exceeds a threshold, comparing to flat unperturbed structures. Transmissions of flat graphene compressed along zi ... [Appl. Phys. Lett. 100, 052111 (2012)] published Wed Feb 1, 2012.

Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

S. R. Sarath Kumar, Anas I. Abutaha, M. N. Hedhili, and H. N. Alshareef
The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H. All films exhibited degenerate ... [Appl. Phys. Lett. 100, 052110 (2012)] published Wed Feb 1, 2012.

Polarity-dependent photoemission spectra of wurtzite-type zinc oxide

Jesse Williams, Hideki Yoshikawa, Shigenori Ueda, Yoshiyuki Yamashita, Keisuke Kobayashi et al.
The polar surfaces of wurtzite-type zinc oxide (ZnO) were characterized by x-ray photoemission spectroscopy to identify the origin of the polarity dependence of the valence band spectra. A characteristic sub-peak always appeared in the valence band spectra of the (0001) face regardless of the surfac ... [Appl. Phys. Lett. 100, 051902 (2012)] published Wed Feb 1, 2012.

Plasma enables edge-to-center-oriented graphene nanoarrays on Si nanograss

S. Kumar, I. Levchenko, Q. J. Cheng, J. Shieh, and K. Ostrikov
The formation of clearly separated vertical graphene nanosheets on silicon nanograss support is demonstrated. The plasma-enabled, two-stage mask-free process produced self-organized vertical graphenes of a few carbon layers (as confirmed by advanced microanalysis), prominently oriented in the substr ... [Appl. Phys. Lett. 100, 053115 (2012)] published Wed Feb 1, 2012.

Functional plasma polymers deposited in capacitively and inductively coupled plasmas

Dirk Hegemann, Enrico Korner, Shang Chen, Jan Benedikt, and Achim von Keudell
Capacitively and inductively coupled plasmas were investigated in order to deposit functional plasma polymers. Considering plasma chemical and surface processes, comparable films can be obtained with both plasma sources yielding distinctly higher deposition rates for ICP. While the gas phase process ... [Appl. Phys. Lett. 100, 051601 (2012)] published Wed Feb 1, 2012.

Beam-scanning planar lens based on graphene

Hong Ju Xu, Wei Bing Lu, Yun Jiang, and Zheng Gao Dong
One of the most important advantages of graphene is the capability of dynamically tuning its conductivity by means of chemical doping or gate voltage. Based on this property, we propose a planar gradient index graphene-based lens transforming spherical waves of the transverse-magnetic (TM) surface p ... [Appl. Phys. Lett. 100, 051903 (2012)] published Wed Feb 1, 2012.

Gas refractometry using a hollow-core photonic bandgap fiber in a Mach-Zehnder-type interferometer

I. Shavrin, S. Novotny, A. Shevchenko, and H. Ludvigsen
We present the design of a fiber-optic gas refractometer that enables spectrally resolved measurements of both real and imaginary parts of the complex refractive index. The proposed concept is based on a Mach-Zehnder-type interferometer with a hollow-core photonic bandgap fiber in one of the interfe ... [Appl. Phys. Lett. 100, 051106 (2012)] published Tue Jan 31, 2012.

Recombination mechanisms and band alignment of GaAsBi/GaAs light emitting diodes

N. Hossain, I. P. Marko, S. R. Jin, K. Hild, S. J. Sweeney et al.
We investigate the temperature and pressure dependence of the light-current characteristics and electroluminescence spectra of GaAsBi/GaAs light emitting diodes. The temperature dependence of the emission wavelength shows a relatively low temperature coefficient of emission peak shift of 0.19 0.01 ... [Appl. Phys. Lett. 100, 051105 (2012)] published Tue Jan 31, 2012.

Deep traps in nonpolar m-plane GaN grown by ammonia-based molecular beam epitaxy

Contact transport of focused ion beam-deposited Pt to Si nanowires: From measurement to understanding

J. J. Ke, K. T. Tsai, Y. A. Dai, and J. H. He
The Si nanowires (NWs) were contacted by focused ion beam (FIB)-deposited Pt as the Ohmic contacts. Ultralow specific contact resistivity of 1.2 x 10 Omega-cm has been measured. Due to the focused ion beam-induced amorphization of Si NWs, contact behavior is explained by diffusion theory, allowing ... [Appl. Phys. Lett. 100, 053503 (2012)] published Tue Jan 31, 2012.

Structural phase transition of graphene caused by GaN epitaxy

Y. Gohda and S. Tsuneyuki
We report first-principles predictions, where the structure of graphene changes drastically with the epitaxial growth of GaN (which has been performed experimentally). We identify GaN-sqrt(3) x sqrt(3)/graphene-2 x 2 superstructure as the most probable interface atomic structure, where three C-C b ... [Appl. Phys. Lett. 100, 053111 (2012)] published Tue Jan 31, 2012.

Epitaxial Cr on n-SrTiO(001)An ideal Ohmic contact

C. Capan, G. Y. Sun, M. E. Bowden, and S. A. Chambers
Epitaxial Cr metallizations grown on n-SrTiO(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO layer, no reduction of the SrTiO, and a near-perfect Ohmic contact. Cr/n-SrTiO(001) thus constitutes an ideal interface between a pure metal ... [Appl. Phys. Lett. 100, 052106 (2012)] published Tue Jan 31, 2012.

Temperature and humidity effects on superhydrophobicity of nanocomposite coatings

Yong Han Yeong, Adam Steele, Eric Loth, Ilker Bayer, Guillaume De Combarieu et al.
This work investigates temperature and humidity effects on the superhydrophobicity of polyurethane/organoclay nanocomposites. Previous reports of superhydrophobic degradation at decreasing surface temperatures for both low and high humidity were generally conducted in open environments. However, the ... [Appl. Phys. Lett. 100, 053112 (2012)] published Tue Jan 31, 2012.

Speed enhancement of multi-particle chain in a traveling standing wave

Martin Siler, Tomas Cizmar, and Pavel Zemanek
A moving array of optical traps created by interference of two counter-propagating evanescent waves has been used for delivery of particle chains up to 18 micro-particles long immersed in water. The particles were optically self-arranged into a linear chain with well-separated distances between them ... [Appl. Phys. Lett. 100, 051103 (2012)] published Tue Jan 31, 2012.

Enhanced efficiency of organic light-emitting devices with metallic electrodes by integrating periodically corrugated structure

Yan-Gang Bi, Jing Feng, Yun-Fei Li, Yu Jin, Yue-Feng Liu et al.
Photons trapped in form of surface-plasmon polariton (SPP) modes associated with the metallic electrode/organic interface results in a large energy loss in organic light-emitting devices (OLEDs). We demonstrate efficient outcoupling of SPP modes from one of two metal electrodes by integrating a peri ... [Appl. Phys. Lett. 100, 053304 (2012)] published Tue Jan 31, 2012.

Unipolar depletion-load organic circuits on flexible substrate by self-organized polymer blending with 6, 13-bis(triisopropylsilylethynyl)pentacene using ink-jet printing

Sung Hoon Kim, Hye Rim Hwang, Ho Joong Kwon, and Jin Jang
We report the threshold voltage control and its application to electronic circuits of ink-jet printed organic thin-film transistors (OTFTs) with self-organized process using 6, 13-bis(triisopropylsilyl-ethynyl)pentacene (TIPS-pentacene) and insulating polymer on plastic substrate. The threshold volt ... [Appl. Phys. Lett. 100, 053302 (2012)] published Tue Jan 31, 2012.

Pseudobinary AlTe-SbTe material for high speed phase change memory application

Kun Ren, Feng Rao, Zhitang Song, Shilong Lv, Yan Cheng et al.
AlSbTe is a pseudobinary material constructed by SbTe (fast crystallization speed but thermally unstable) and AlTe (thermally stable but without memory switching ability). AlSbTe material possesses advantages of these two binary compounds showing good memory switching ability with fast switching spe ... [Appl. Phys. Lett. 100, 052105 (2012)] published Tue Jan 31, 2012.

Spin transport in poly(metalarenylsilane)

Yukihito Matsuura
We focused on the spin transport properties of polymers containing ferrocene and the related transition-metal-benzene sandwich compound (metal = Cr and V) with a silicon bridge such as poly(ferrocenylsilane) and poly(metalarenylsilane). As a model system, a sulfur-substituted oligomer was put on gol ... [Appl. Phys. Lett. 100, 053303 (2012)] published Tue Jan 31, 2012.

Fabrication and magnetic properties of free-standing Ni nanotube arrays with controllable wall thickness

Y. L. Li, S. L. Tang, R. Xie, Y. Wang, M. Yang et al.
Free-standing Ni nanotubes were fabricated on silicon substrate using anodic aluminum oxide/polypyrrole composite template. The diameter, length, and wall thickness of the nanotubes can be precisely and independently controlled. Magnetic measurements show that the magnetic anisotropic properties are ... [Appl. Phys. Lett. 100, 052402 (2012)] published Tue Jan 31, 2012.

Tapping-mode force spectroscopy using cantilevers with interferometric high-bandwidth force sensors

A. Fatih Sarioglu, Sergei Magonov, and Olav Solgaard
We quantitatively map the surface forces and elastic modulus in tapping-mode atomic force microscopy (AFM). To achieve this, we use custom-built cantilevers with interferometric high-bandwidth force sensors that can resolve nonlinear tip-sample interaction forces, combined with a set of algorithms t ... [Appl. Phys. Lett. 100, 053109 (2012)] published Tue Jan 31, 2012.

Self-driving capacitive cantilevers for high-frequency atomic force microscopy

Keith A. Brown, Benjamin H. Yang, and R. M. Westervelt
We demonstrate a simple way to actuate an atomic force microscope cantilever at high frequencies by electrically driving a thin-film capacitor on its surface. Capacitive driving directly actuates the vibrational mode of the cantilever, removing the effects of unwanted mechanical modes present in con ... [Appl. Phys. Lett. 100, 053110 (2012)] published Tue Jan 31, 2012.

Itinerant ferromagnetism and geometrically suppressed metal-insulator transition in epitaxial thin films of CaRuO

Ludi Miao, Punam Silwal, Xiaolan Zhou, Ilan Stern, Jin Peng et al.
We have investigated the effect of epitaxial strain on the electrical and magnetic properties of high quality CaRuO films on LaAlO (001) substrates. The films exhibit low temperature itinerant ferromagnetic ground state and significantly suppressed metal-insulator transition due to epitaxial strain. ... [Appl. Phys. Lett. 100, 052401 (2012)] published Tue Jan 31, 2012.

From mesoscopic to global polar order in the uniaxial relaxor ferroelectric SrBaNbO

J. Dec, W. Kleemann, V. V. Shvartsman, D. C. Lupascu, and T. Lukasiewicz
In the relaxor ferroelectric SrBaNbO (SBN80) the relaxation of polar nanoregions (PNRs) reveals an anisotropic breathing mode when approaching the transition temperature, T [approximate] 289 K, on cooling. Two distinct dispersion steps and peaks, respectively, of the complex susceptibility component ... [Appl. Phys. Lett. 100, 052903 (2012)] published Tue Jan 31, 2012.

Ultrathin crystalline-silicon solar cells with embedded photonic crystals

Shrestha Basu Mallick, Mukul Agrawal, Artit Wangperawong, Edward S. Barnard, Kaushal K. Singh et al.
Photonic crystals (PCs) can be used to trap light in thin-film solar cells to increase optical absorption. We fabricated ultrathin c-Si solar cells whose active layer was patterned into a two-dimensional PC with a square lattice of 450 nm diameter holes spaced at a period of 750 nm. The PC couples i ... [Appl. Phys. Lett. 100, 053113 (2012)] published Tue Jan 31, 2012.

Growth and valence band offset measurement of PbTe/InSb heterojunctions

Kyoung-Keun Lee, Weerasinghe Priyantha, and Thomas H. Myers
InSb (111)B and (211)B substrates were investigated for the growth of PbTe. The PbTe/InSb (111)B showed slip features caused by stain relaxation during cooling down, while growth of PbTe/InSb (211)B resulted in a better surface morphology. The valence band offset of PbTe/InSb (211)B was measured by ... [Appl. Phys. Lett. 100, 052108 (2012)] published Tue Jan 31, 2012.

2-bit operation based on modulated Fowler-Nordheim tunneling in charge-trapping flash memory cell

Min-Feng Hung, Yung-Chun Wu, and Jiang-Hung Chen
This work proposes a spatially charge tunneling method for program/erase (P/E) based on the drain-modulated Fowler-Nordheim (MFN) tunneling in a polycrystalline silicon channel charge-trap type flash memory device. The program mechanism and the simulation of the MFN are discussed. 2-bit operations b ... [Appl. Phys. Lett. 100, 052107 (2012)] published Tue Jan 31, 2012.

Short circuit current improvement in planar heterojunction organic solar cells by multijunction charge transfer

J. C. Wang, S. Q. Shi, C. W. Leung, S. P. Lau, K. Y. Wong et al.
A multijunction structure was applied on an organic photovoltaic (OPV) device for broadening the absorption spectrum and enhancing the power conversion efficiency through charge transfer process. By inserting the tris[4-(2-thienyl)]amine (TTPA) into a boron subphthalocyanine chloride (SubPc)/C OPV d ... [Appl. Phys. Lett. 100, 053301 (2012)] published Mon Jan 30, 2012.

Fabrication and characterization of ambipolar devices on an undoped AlGaAs/GaAs heterostructure

J. C. H. Chen, D. Q. Wang, O. Klochan, A. P. Micolich, K. Das Gupta et al.
We have fabricated AlGaAs/GaAs heterostructure devices in which the conduction channel can be populated with either electrons or holes simply by changing the polarity of a gate bias. The heterostructures are entirely undoped, and carriers are, instead, induced electrostatically. We use these devices ... [Appl. Phys. Lett. 100, 052101 (2012)] published Mon Jan 30, 2012.

Influence of charge compensation mechanisms on the sheet electron density at conducting LaAlO/SrTiO-interfaces

F. Gunkel, P. Brinks, S. Hoffmann-Eifert, R. Dittmann, M. Huijben et al.
The equilibrium conductance of LaAlO/SrTiO (LAO/STO)-heterointerfaces was investigated at high temperatures (950 K-1100 K) as a function of ambient oxygen partial pressure (pO). Metallic LAO/STO-interfaces were obtained for LAO grown on STO single crystals as well as on STO-buffered (La,Sr)(Al,Ta)O ... [Appl. Phys. Lett. 100, 052103 (2012)] published Mon Jan 30, 2012.

Spoof-like plasmonic behavior of plasma enhanced atomic layer deposition grown Ag thin films

S. M. Prokes, O. J. Glembocki, Erin Cleveland, Josh D. Caldwell, Edward Foos et al.
The plasmonic behavior of Ag thin films produced by plasma enhanced atomic layer deposition (PEALD) has been investigated. We show that as-deposited flat PEALD Ag films exhibit unexpected plasmonic properties, and the plasmonic enhancement can differ markedly, depending on the microstructure of the ... [Appl. Phys. Lett. 100, 053106 (2012)] published Mon Jan 30, 2012.

Magnetodielectric effects of YFeTiO ceramics

Y. J. Wu, C. Yu, X. M. Chen, and J. Li
Dielectric, magnetic, and magnetodielectric properties of YFeTiO (x = 0, 0.1, 0.2) ceramics were investigated. Ti substitution induces a low temperature dielectric relaxation which comes from the charge carrier hopping between Ti and Ti. The Maxwell-Wagner effect related dielectric relaxation become ... [Appl. Phys. Lett. 100, 052902 (2012)] published Mon Jan 30, 2012.

Effect of electric field on the band structure of graphene/boron nitride and boron nitride/boron nitride bilayers

Radhakrishnan Balu, Xiaoliang Zhong, Ravindra Pandey, and Shashi P. Karna
Effect of electric field on the band structures of graphene/boron nitride (BN) and BN/BN bilayers is investigated within the framework of density functional theory. The calculated bandgap of the graphene/BN bilayer increases, although by small amount, with applied electric field. In the case of BN/B ... [Appl. Phys. Lett. 100, 052104 (2012)] published Mon Jan 30, 2012.

Quantum Hall effect in bottom-gated epitaxial graphene grown on the C-face of SiC

B. Jouault, N. Camara, B. Jabakhanji, A. Caboni, C. Consejo et al.
We demonstrate that the carrier concentration of epitaxial graphene devices grown on the C-face of a SiC substrate is efficiently modulated by a buried gate. The gate is fabricated via the implantation of nitrogen atoms in the SiC crystal. The charge neutrality point is observed close to gate voltag ... [Appl. Phys. Lett. 100, 052102 (2012)] published Mon Jan 30, 2012.

Non-ideal energy selective contacts and their effect on the performance of a hot carrier solar cell with an indium nitride absorber

Y. Feng, P. Aliberti, B. P. Veettil, R. Patterson, S. Shrestha et al.
The hot carrier solar cell is a third generation photovoltaic device that extracts photo-generated carriers before they thermalise. In this work, the efficiency of a hot carrier solar cell with a 50 nm indium nitride (InN) absorber layer has been calculated, taking into account the realistic transpo ... [Appl. Phys. Lett. 100, 053502 (2012)] published Mon Jan 30, 2012.

Comparison of scanning tunneling microscope-light emission and photoluminescence from porphyrin films using ultra-high vacuum scanning tunneling microscopy

Ryusuke Nishitani, Hongwen Liu, and Hiroshi Iwasaki
In order to study the interaction between molecules and photon fields, including plasmonic and external laser fields, we have carried out in situ measurements of photoluminescence (PL) from porphyrin molecules on Au substrates with and without a scanning tunneling microscope (STM) tip. Measurements ... [Appl. Phys. Lett. 100, 051102 (2012)] published Mon Jan 30, 2012.