Applied Physics Letters: All Topics

Demonstration of enhanced absorption in thin film Si solar cells with textured photonic crystal back reflector

L. Zeng, P. Bermel, Y. Yi, B. A. Alamariu, K. A. Broderick et al.
Herein the authors report the experimental application of a powerful light trapping scheme, the textured photonic crystal (TPC) backside reflector, to thin film Si solar cells. TPC combines a one-dimensional photonic crystal as a distributed Bragg reflector with a diffraction grating. Light absorpti ... [Appl. Phys. Lett. 93, 221105 (2008)] published Mon Dec 1, 2008.

Molecular dynamics simulations of buckling-induced plasticity

Julien Durinck, Christophe Coupeau, Jerome Colin, and Jean Grilhe
Molecular dynamics simulations of thin film buckling demonstrate that high compressive stresses are localized in the straight-sided wrinkle leading to the nucleation of dislocations, which are mobile and plastically release a large amount of the strain. As a consequence, the maximum deflection deter ... [Appl. Phys. Lett. 93, 221904 (2008)] published Mon Dec 1, 2008.

Microdischarge propagation and expansion in a surface dielectric barrier discharge

A. R. Hoskinson, L. Oksuz, and N. Hershkowitz
We have recorded light emission from a surface dielectric barrier discharge with one exposed and one insulated electrode using an intensified digital camera. The discharge was operated in atmospheric pressure air. When the voltage to the exposed electrode is increasing, streamers form and propagate ... [Appl. Phys. Lett. 93, 221501 (2008)] published Mon Dec 1, 2008.

High optimization process for increasing the attenuation properties of acoustic metamaterials by means of the creation of defects

V. Romero-Garcia, J. V. Sanchez-Perez, L. M. Garcia-Raffi, J. M. Herrero, S. Garcia-Nieto et al.
An improvement in the attenuation capabilities of acoustic metamaterials by means of the creation of defects is considered here as a multiobjective optimization problem. From this point of view, it is possible to define the optimum strategy in the creation of defects to achieve an important increase ... [Appl. Phys. Lett. 93, 223502 (2008)] published Mon Dec 1, 2008.

Charge storage characteristics of Mo nanocrystal dependence on Mo oxide reduction

Chao-Cheng Lin, Ting-Chang Chang, Chun-Hao Tu, Wei-Ren Chen, Chih-Wei Hu et al.
An oxygen incorporated Mo silicide was explored to form the Mo nanocrystals after rapid thermal annealing. Transmission electron microscopy showed the nanocrystals embedded in SiO. Charge storage characteristics of Mo nanocrystals influenced by the Mo oxide and the surrounding oxide were investigate ... [Appl. Phys. Lett. 93, 222101 (2008)] published Mon Dec 1, 2008.

Light-emitting polymer space-charge-limited transistor

Chun-Yu Chen, Yu-Chiang Chao, Hsin-Fei Meng, and Sheng-Fu Horng
Polymer light-emitting transistor is realized by vertically stacking a top-emitting polymer light-emitting diode on a polymer space-charge-limited transistor. The transistor modulates the current flow of the light-emitting diode by the metal-grid base voltage. The active semiconductor of the transis ... [Appl. Phys. Lett. 93, 223301 (2008)] published Mon Dec 1, 2008.

Improved endurance behavior of resistive switching in (Ba,Sr)TiO[sub 3] thin films with W top electrode

Wan Shen, Regina Dittmann, Uwe Breuer, and Rainer Waser
We compared the resistive switching performance of barium strontium titanate (BST) thin films with tungsten (W) and platinum (Pt) top electrodes, respectively. The yield, endurance, and reliability were strongly improved for the samples with W top electrode. Whereas the samples with Pt top electrode ... [Appl. Phys. Lett. 93, 222102 (2008)] published Mon Dec 1, 2008.

Shrinkage and expansion mechanisms of SiO[sub 2] elliptical membrane nanopores

Jae Won Shin, Jeong Yong Lee, Do Hyun Oh, Tae Whan Kim, and Woon Jo Cho
20 nm SiO elliptical membrane nanopores with various thicknesses were directly formed in situ by using a focused electron beam with transmission electron microscopy (TEM). The shrinkage and the expansion behaviors of the SiO ellipse nanopores with different thicknesses were attributed to variations ... [Appl. Phys. Lett. 93, 221903 (2008)] published Mon Dec 1, 2008.

Room-temperature nanolaser from CdSe nanotubes embedded in anodic aluminum oxide nanocavity arrays

Tsung-Ju Lin, Hsin-Liang Chen, Yang-Fang Chen, and Soofin Cheng
Room-temperature visible lasing in CdSe semiconductor nanotube arrays embedded in anodic aluminum oxide template has been demonstrated. The cylindrical nanocavities of anodic aluminum oxide template form laser resonators, and the laser oscillation was achieved through whispering gallery mode gain fr ... [Appl. Phys. Lett. 93, 223903 (2008)] published Mon Dec 1, 2008.

Effect of quantity and configuration of attached bacteria on bacterial propulsion of microbeads

Bahareh Behkam and Metin Sitti
Flagellated chemotactic bacteria have been utilized as actuators for propulsion of polystyrene microbeads by randomly attaching several bacteria on their surface. In this work, a plasma-based bacteria patterning technique is developed and used to limit bacteria attachment to approximately half of th ... [Appl. Phys. Lett. 93, 223901 (2008)] published Mon Dec 1, 2008.

Ag nanoparticle dispersed PbTiO[sub 3] percolative composite thin film with high permittivity

Zongrong Wang, Tao Hu, Liwen Tang, Ning Ma, Chenlu Song et al.
Ag nanoparticle dispersed PbTiO percolative composite thin films were prepared in situ by sol-gel method using Pb(NO), Ti(CHO), and AgNO as raw materials and lactic acid along with citric acid as complexing agent. The size of the Ag nanoparticles measured by ultraviolet-visible spectra is about 3 n ... [Appl. Phys. Lett. 93, 222901 (2008)] published Mon Dec 1, 2008.

Low-temperature sterilization of wrapped materials using flexible sheet-type dielectric barrier discharge

Hiroyuki Eto, Yoshihito Ono, Akihisa Ogino, and Masaaki Nagatsu
A flexible sheet-type dielectric barrier discharge (DBD) was studied for the low-temperature sterilization of medical instruments wrapped with Tyvek packaging. Sterilization experiments using Geobacillus stearothermophilus spores with a population of 10 were carried out with various mixtures of nitr ... [Appl. Phys. Lett. 93, 221502 (2008)] published Mon Dec 1, 2008.

Lateral-driven continuous magnetophoretic separation of blood cells

Jinhee Jung and Ki-Ho Han
We present a method for the lateral-driven continuous magnetophoretic separation of red and white blood cells from peripheral whole blood, based on their native magnetic properties. The separation is achieved using a high-gradient magnetic field, caused by a ferromagnetic wire array inlaid on glass ... [Appl. Phys. Lett. 93, 223902 (2008)] published Mon Dec 1, 2008.

Electron doping of small-diameter carbon nanotubes with exohedral fullerenes

Basudev Pradhan, Ryan R. Kohlmeyer, Kristina Setyowati, and Jian Chen
The interaction between carbon nanotubes (CNTs) and exohedral fullerenes, which represent two types of carbon allotropes with extraordinary properties, has received little attention so far. The effect of exohedral fullerenes on CNTs' electronic properties is essentially unknown. We report the electr ... [Appl. Phys. Lett. 93, 223102 (2008)] published Mon Dec 1, 2008.

Twisted liquid crystal pi cell stabilized by polymer-sustained alignment

Tien-Jung Chen, Yuan-Hsin Cheng, and Sheng-Ming Wu
A uniform pi-twist liquid crystal (LC) alignment was stabilized in a pi cell by photopolymerization of a minute amount of monomers without using any chiral material. Controlling UV exposure time can vary the LC pretilt angle to achieve a stabilized pi-twist state. This type of pi-twisted LC cell mad ... [Appl. Phys. Lett. 93, 221103 (2008)] published Mon Dec 1, 2008.

Stress gradients induced in Cu films by capping layers

Conal E. Murray, Paul R. Besser, Christian Witt, and Jean L. Jordan-Sweet
The presence of capping layers deposited on copper films can create strain gradients through the Cu film thickness. Grazing-incidence and conventional x-ray diffraction measurements determined the in-plane stress of the Cu films as a function of depth. Cu films possessing a SiCNH capping layer exhib ... [Appl. Phys. Lett. 93, 221901 (2008)] published Mon Dec 1, 2008.

Ultrahigh-brightness 850 nm GaAs/AlGaAs photonic crystal laser diodes

K. Posilovic, T. Kettler, V. A. Shchukin, N. N. Ledentsov, U. W. Pohl et al.
One-dimensional photonic crystal lasers emitting in the 850 nm range show high internal quantum efficiencies of 93% and very narrow vertical beam divergence of 7.1 degrees (full width at half maximum). 50 [mu]m broad area lasers with unpassivated facets exhibit a high total output power of nearly ... [Appl. Phys. Lett. 93, 221102 (2008)] published Mon Dec 1, 2008.

Piezoresponse force microscopy on doubly clamped KNbO[sub 3] nanowires

J. Wang, C. Stampfer, C. Roman, W. H. Ma, N. Setter et al.
We present piezoresponse force microscopy measurements on individual integrated potassium niobate (KNbO) nanowires. The devices consist of KNbO nanowires on SiO substrates being mechanically clamped and electrically biased by lithographically defined metal electrodes. This configuration allows to ap ... [Appl. Phys. Lett. 93, 223101 (2008)] published Mon Dec 1, 2008.

Ultrathin AlN/GaN heterostructure field-effect transistors with deposition of Si atoms on AlN barrier surface

Norio Onojima, Nobumitsu Hirose, Takashi Mimura, and Toshiaki Matsui
We deposited Si atoms on the AlN barrier surface of an ultrathin AlN/GaN heterostructure field-effect transistor (HFET). This induced a remarkable change in the electrical properties of the two-dimensional electron gas. A 2-nm-thick Si layer reduced the sheet resistance of an AlN/GaN HFET (AlN barri ... [Appl. Phys. Lett. 93, 223501 (2008)] published Mon Dec 1, 2008.

Escape dynamics of a few electrons in a single-electron ratchet using silicon nanowire metal-oxide-semiconductor field-effect transistor

Satoru Miyamoto, Katsuhiko Nishiguchi, Yukinori Ono, Kohei M. Itoh, and Akira Fujiwara
Transport dynamics of a few electrons in a quantum dot are investigated in a single-electron ratchet using silicon nanowire metal-oxide-semiconductor field-effect transistors. Time-resolved measurements in a nanosecond regime are carried out to determine the escape times of the first, second, and th ... [Appl. Phys. Lett. 93, 222103 (2008)] published Mon Dec 1, 2008.

Ground-state charge-transfer complex formation in hybrid poly(3-hexyl thiophene):titanium dioxide solar cells

I. Haeldermans, K. Vandewal, W. D. Oosterbaan, A. Gadisa, J. D'Haen et al.
The existence of a ground-state charge-transfer (CT) complex in a conjugated polymer:metal oxide nanoparticle bulk heterojunction photovoltaic cell is demonstrated by Fourier-transform photocurrent spectroscopy (FTPS). The CT complex between poly(3-hexylthiophene) (P3HT) and titanium dioxide (TiO) i ... [Appl. Phys. Lett. 93, 223302 (2008)] published Mon Dec 1, 2008.

GaN nanostructured p-i-n photodiodes

J. L. Pau, C. Bayram, P. Giedraitis, R. McClintock, and M. Razeghi
We report the fabrication of nanostructured p-i-n photodiodes based on GaN. Each device comprises arrays of ~200 nm diameter and 520 nm tall nanopillars on a 1 [mu]m period, fabricated by e-beam lithography. Strong rectifying behavior was obtained with an average reverse current per nanopillar of ... [Appl. Phys. Lett. 93, 221104 (2008)] published Mon Dec 1, 2008.

Structure of chemically derived mono- and few-atomic-layer boron nitride sheets

Wei-Qiang Han, Lijun Wu, Yimei Zhu, Kenji Watanabe, and Takashi Taniguchi
We prepared mono- and few-layer hexagonal boron nitride sheets by a chemical-solution-derived method starting from single-crystalline hexagonal boron nitride. Using high-resolution transmission electron microscopy and electron-energy-loss spectrometry, we characterized the microstructure, compositio ... [Appl. Phys. Lett. 93, 223103 (2008)] published Mon Dec 1, 2008.

Effect of C incorporation on relaxation of SiGe/Si

H.-W. Kim, S. Choi, S. Hong, H. K. Jung, G.-D. Lee et al.
Thin fully strained SiGe/SiGeC/SiGe heterostructures (x=0.2), with controlled C incorporation sites, were grown on Si substrates using ultrahigh vacuum chemical vapor deposition. Following the growth, layers were relaxed using rapid thermal annealing at 1000 degrees C for 30 s, and high degrees of ... [Appl. Phys. Lett. 93, 221902 (2008)] published Mon Dec 1, 2008.

Refractive index modulation in periodically poled MgO-doped congruent LiNbO[sub 3] crystal

Yunlin Chen, He Zhan, and Bo Zhou
An optical diffraction method is exploited to characterize periodically poled MgO-doped congruent LiNbO crystal fabricated by electric induced technique. The optical diffraction patterns indicate that the refractive index changes occur in periodic domain structures. Light diffraction from this type ... [Appl. Phys. Lett. 93, 222902 (2008)] published Mon Dec 1, 2008.

Enhanced linearly polarized lasing emission from nanoimprinted surface-emitting distributed feedback laser based on polymeric liquid crystals

Soon Moon Jeong, Na Young Ha, Mu Guen Chee, Fumito Araoka, Ken Ishikawa et al.
The authors have demonstrated the enhancement of linearly polarized lasing emission intensity using a structure made by a simple fabrication process. The enhanced lasing is achieved using a nanoimprinted distributed feedback structure together with spin-coated polymeric liquid crystals. The backward ... [Appl. Phys. Lett. 93, 221101 (2008)] published Mon Dec 1, 2008.

Electrical and reliability characteristics of copper-doped carbon (CuC) based resistive switching devices for nonvolatile memory applications

Myeongbum Pyun, Hyejung Choi, Ju-Bong Park, Dongsoo Lee, Musarrat Hasan et al.
We have investigated copper-doped carbon (CuC) as a new solid-state electrolyte material for resistive switching devices. Compared with CuS electrolytes, CuC devices demonstrate good memory characteristics such as a high resistance ratio of over two orders, higher operation voltage, and high tempera ... [Appl. Phys. Lett. 93, 212907 (2008)] published Wed Nov 26, 2008.

High quantum efficiency back-illuminated GaN avalanche photodiodes

C. Bayram, J. L. Pau, R. McClintock, M. Razeghi, M. P. Ulmer et al.
Back-illuminated avalanche photodiodes (APDs) composed of heterojunctions of either p-GaN/i-GaN/n-AlGaN or p-GaN/i-GaN/n-GaN/n-AlGaN were fabricated on AlN templates. At low voltage, an external quantum efficiency of 57% at 352 nm with a bandpass response was achieved by using AlGaN in the n-layer. ... [Appl. Phys. Lett. 93, 211107 (2008)] published Wed Nov 26, 2008.

Surface potential of n- and p-type GaN measured by Kelvin force microscopy

S. Barbet, R. Aubry, M.-A. di Forte-Poisson, J.-C. Jacquet, D. Deresmes et al.
n- and p-type GaN epitaxial layers grown by metal-organic chemical vapor deposition with different doping levels have been characterized by Kelvin probe force microscopy (KFM). To investigate the surface states of GaN beyond instrumental and environmental fluctuations, a KFM calibration procedure us ... [Appl. Phys. Lett. 93, 212107 (2008)] published Wed Nov 26, 2008.

Localized heating in nanoscale Pt constrictions measured using blackbody radiation emission

Daniel R. Ward, Naomi J. Halas, and Douglas Natelson
Using thermal emission microscopy, we investigate heating in Pt nanowires before and during electromigration. The wires are observed to reach temperatures in excess of 1000 K. This is beyond the thermal decomposition threshold for many organic molecules of interest for single molecule measurements w ... [Appl. Phys. Lett. 93, 213108 (2008)] published Wed Nov 26, 2008.

Characterization of complementary electric field coupled resonant surfaces

Thomas H. Hand, Jonah Gollub, Soji Sajuyigbe, David R. Smith, and Steven A. Cummer
We present angle-resolved free-space transmission and reflection measurements of a surface composed of complementary electric inductive-capacitive (CELC) resonators. By measuring the reflection and transmission coefficients of a CELC surface with different polarizations and particle orientations, we ... [Appl. Phys. Lett. 93, 212504 (2008)] published Wed Nov 26, 2008.

Single mode emitting ridge waveguide quantum cascade lasers coupled to an active ring resonator filter

Julia Semmel, Wolfgang Kaiser, Holger Hofmann, Sven Hofling, and Alfred Forchel
Quantum cascade ridge waveguide lasers with coupled ring resonators have been fabricated. Coupling of an actively pumped microring resonator to a ridge waveguide device allows for filtering the numerous FabryPerot modes emerging in the ridge waveguide. Due to the large free spectral range of the rin ... [Appl. Phys. Lett. 93, 211106 (2008)] published Wed Nov 26, 2008.

Organic/inorganic hybrid complementary circuits based on pentacene and amorphous indium gallium zinc oxide transistors

Jong H. Na, M. Kitamura, and Y. Arakawa
Complementary inverters composed of pentacene for the p-channel thin-film transistors (TFTs) and amorphous indium gallium zinc oxide for the n-channel TFTs have been fabricated on glass substrates. The p- and n-channel TFTs have field-effect mobilities of 0.6 and 17.1 cm/V s, respectively, and inve ... [Appl. Phys. Lett. 93, 213505 (2008)] published Wed Nov 26, 2008.

Surface plasmon excitation of Au and Ag in scanning probe energy loss spectroscopy

A. Pulisciano, S. J. Park, and R. E. Palmer
We explore the incident energy dependence of the electronic excitation spectra of Au and Ag films in scanning probe energy loss spectroscopy (SPELS) and also high resolution electron energy loss spectroscopy. We show that the spectra obtained in SPELS depend strongly on the incident electron beam en ... [Appl. Phys. Lett. 93, 213109 (2008)] published Wed Nov 26, 2008.

Solution-processed carbon electrodes for organic field-effect transistors

Hiroshi Wada and Takehiko Mori
Bottom-contact organic transistors with carbon-paste electrodes are fabricated by means of the surface selective deposition technique, where a carbon-paste solution is deposited on the region in which the self-assembled monolayers are removed by ultraviolet light irradiation. The resulting bottom-co ... [Appl. Phys. Lett. 93, 213303 (2008)] published Wed Nov 26, 2008.

Dynamic bias stress current instability caused by charge trapping and detrapping in pentacene thin film transistors

T. Miyadera, T. Minari, S. D. Wang, and K. Tsukagoshi
The current instability in pentacene organic thin film transistors (OTFTs) under dynamic bias stress was investigated. Current instability is strongly influenced by pulse duty ratio and pulse on-period and off-period voltages, but is independent of pulse frequency. A stable on-current without curren ... [Appl. Phys. Lett. 93, 213302 (2008)] published Wed Nov 26, 2008.

Spin-glass-like behavior caused by Mn-rich Mn(Ga)As nanoclusters in GaAs

C. H. Chang and T. M. Hong
We simulate the indirect exchange interaction between Mn-rich Mn(Ga)As nanoclusters in GaAs by analytical means. In contrast to the conventional RudermanKittelKasuyaYosida (RKKY) formula, which considers the mediation by the carriers in the medium, we also include the contribution from those inside ... [Appl. Phys. Lett. 93, 212106 (2008)] published Wed Nov 26, 2008.

Nanowire field-effect transistor with Bi[sub 1.5]Zn[sub 1.0]Nb[sub 1.5]O[sub 7] dielectric

Wangyang Fu, Zhi Xu, Kaihui Liu, Wenlong Wang, Xuedong Bai et al.
In this letter, amorphous BiZnNbO films with large permittivity (~70) are prepared as the gate dielectric for ZnO nanowire field-effect transistors by using low-temperature (~100 degrees C) pulsed laser deposition. The transistors exhibit a low operation gate voltage (<3 V), a high carrier mobili ... [Appl. Phys. Lett. 93, 213107 (2008)] published Wed Nov 26, 2008.

Metal patterning using maskless vacuum evaporation process based on selective deposition of photochromic diarylethene

Rie Takagi, Kyoko Masui, Shinichiro Nakamura, and Tsuyoshi Tsujioka
We developed an electrode/wiring patterning method that does not employ evaporation shadow masks; this method is based on selective metal deposition of photochromic diarylethene (DAE). In the selective Mg deposition based on the photoisomerization of DAE, Mg vapor atoms are deposited only on colored ... [Appl. Phys. Lett. 93, 213304 (2008)] published Wed Nov 26, 2008.

Reversible charge injection in antiferroelectric thin films

A. Q. Jiang, T. A. Tang, S. Corkovic, and Q. Zhang
High-energy storage antiferroelectric capacitors operated in a high speed require the quick release of stored charges after the removal of the electrical field accompanying ferroelectric-to-antiferroelectric phase transition. However, the phase-transition time can vary from a few nanoseconds to mill ... [Appl. Phys. Lett. 93, 212908 (2008)] published Wed Nov 26, 2008.

Terahertz wave generation via optical rectification from multiferroic BiFeO[sub 3]

D. Talbayev, Seongsu Lee, S.-W. Cheong, and A. J. Taylor
We detected broadband coherent terahertz emission from multiferroic BiFeO after illuminating a high-quality bulk single ferroelectric domain crystal with an ~100 fs optical pulse. The dependence of the emitted terahertz waveform on the energy and polarization of the optical pulse is consistent with ... [Appl. Phys. Lett. 93, 212906 (2008)] published Wed Nov 26, 2008.

Giant magnetoelectric effect in mechanically clamped heterostructures of magnetostrictive alloy and piezoelectric crystal-alloy cymbal

Yaojin Wang, Siu Wing Or, Helen Lai Wa Chan, Xiangyong Zhao, and Haosu Luo
We experimentally and theoretically report a giant magnetoelectric (ME) effect in a heterostructure made by clamping a bar-shaped magnetostrictive TbDyFe (Terfenol-D) alloy actuator and a cymbal-type piezoelectric 0.7Pb(MgNb)O0.3PbTiO(PMNPT) (PMN-PT) single crystal-brass alloy transducer in a brass ... [Appl. Phys. Lett. 93, 213504 (2008)] published Wed Nov 26, 2008.

Theory of exciton-polariton lasing at room temperature in ZnO microcavities

R. Johne, D. D. Solnyshkov, and G. Malpuech
We use the semiclassical Boltzmann equations to describe the exciton-polariton relaxation in a bulk ZnO microcavity at room temperature. We present kinetic phase diagrams which report the lasing threshold versus the main sample parameters, such as the polariton lifetime or the value of the Rabi spli ... [Appl. Phys. Lett. 93, 211105 (2008)] published Wed Nov 26, 2008.

Scaling behaviors of reset voltages and currents in unipolar resistance switching

S. B. Lee, S. C. Chae, S. H. Chang, J. S. Lee, S. Seo et al.
The wide distributions of switching voltages in unipolar switching currently pose major obstacles for scientific advancement and practical applications. Using NiO capacitors, we investigated the distributions of the reset voltage and current. We found that they scaled with the resistance value R in ... [Appl. Phys. Lett. 93, 212105 (2008)] published Tue Nov 25, 2008.

High order mode oscillation in a terahertz photonic-band-gap multibeam reflex klystron

Kyu-Ha Jang, Seok-Gy Jeon, Jung-Il Kim, Jong-Hyo Won, Jin-Kyu So et al.
TM-like higher order mode was excited in a multibeam reflex klystron oscillator employing a hybrid photonic-band-gap (PBG) cavity using a three-dimensional particle-in-cell simulation. One side of a conventional metal cavity was replaced with a dielectric photonic crystal lattice to form a hybrid PB ... [Appl. Phys. Lett. 93, 211104 (2008)] published Tue Nov 25, 2008.

Optical response from lenslike semiconductor nipple arrays

H.-M. Wu, C.-M. Lai, and L.-H. Peng
The authors reported the use of recessive size reduction in self-assembled polystyrene sphere mask with anisotropic etching to form lenslike nipple arrays onto the surface of silicon and gallium nitride. These devices are shown to exhibit a filling factor near to an ideal close-packed condition and ... [Appl. Phys. Lett. 93, 211903 (2008)] published Tue Nov 25, 2008.

Very high-kappa ZrO[sub 2] with La[sub 2]O[sub 3] (LaGeO[sub x]) passivating interfacial layers on germanium substrates

G. Mavrou, P. Tsipas, A. Sotiropoulos, S. Galata, Y. Panayiotatos et al.
Thin LaO (LaGeO) passivating layers combined with ZrO caps form a chemically stable bilayer gate stack on Ge with good electrical properties. The most important observation is that a higher-kappa tetragonal zirconia phase coexists with the most commonly observed monoclinic, increasing the kappa valu ... [Appl. Phys. Lett. 93, 212904 (2008)] published Tue Nov 25, 2008.

Enhanced fluorescence from Eu[sup 3+] in low-loss silica glass-ceramic waveguides with high SnO[sub 2] content

S. N. B. Bhaktha, F. Beclin, M. Bouazaoui, B. Capoen, A. Chiasera et al.
We report on the sol-gel fabrication and characterization of (100x)SiOxSnO (x=8, 16, and 25 mol %) glass-ceramic waveguides doped with 1 mol % Eu. A suitable top-down thermal process led to the formation of SnO nanocrystals ~4 nm embedding Eu ions. The excitation spectra evidence the role of in ... [Appl. Phys. Lett. 93, 211904 (2008)] published Tue Nov 25, 2008.

Polarization-selective resonant photonic crystal photodetector

Jin-Kyu Yang, Min-Kyo Seo, In-Kag Hwang, Sung-Bock Kim, and Yong-Hee Lee
Resonance-assisted photonic crystal (PhC) slab photodetectors are demonstrated by utilizing six 7-nm-thick InGaAsP quantum wells. In order to encourage efficient photon coupling into the slab from the vertical direction, a coupled-dipole-cavity-array PhC structure is employed. Inheriting the charact ... [Appl. Phys. Lett. 93, 211103 (2008)] published Tue Nov 25, 2008.

Enhanced ferroelectric properties of LiNbO[sub 3] substituted Na[sub 0.5]K[sub 0.5]NbO[sub 3] lead-free thin films grown by chemical solution deposition

Chang Won Ahn, Euh Duck Jeong, Sun Young Lee, Hai Joon Lee, Sun Hee Kang et al.
We have fabricated environmental friendly lead-free ferroelectric NaKNbO (NKN) and 0.95NaKNbO0.05LiNbO (0.95NKN-0.05LN) thin films by chemical solution deposition using metal-organic compounds, and studied the effects of LN substitution through the dielectric and ferroelectric properties. The small ... [Appl. Phys. Lett. 93, 212905 (2008)] published Tue Nov 25, 2008.

Solution-processed poly(3-hexylthiophene) vertical organic transistor

Sheng-Han Li, Zheng Xu, Guanwen Yang, Liping Ma, and Yang Yang
The fabrication and operation of a solution-processed vertical organic transistor are now demonstrated. The vertical structure provides a large cross section and a short channel length to counter the inherent limitations of the organic materials. The operation of a vertical organic transistor relies ... [Appl. Phys. Lett. 93, 213301 (2008)] published Tue Nov 25, 2008.

Gigahertz photothermal effect in silicon waveguides

W. H. P. Pernice, Mo Li, and H. X. Tang
We present a theoretical and experimental study of the frequency response of the photothermal effect in silicon waveguides. The effect is studied for modulation frequencies up to 3 GHz using integrated photonic circuits in MachZehnder and ring oscillator configurations. The thermal behavior of sili ... [Appl. Phys. Lett. 93, 213106 (2008)] published Tue Nov 25, 2008.

Synthesis and photoluminescence characteristics of color-tunable BaY[sub 2]ZnO[sub 5]:Eu[sup 3+] phosphors

Chih-Hao Liang, Yee-Cheng Chang, and Yee-Shin Chang
Color-tunable phosphors of BaYEuZnO (x=0.0010.9) were synthesized using a vibrating milled solid state reaction. The results indicate that the emission spectra of BaYEuZnO samples excited at 395 nm exhibit a series of shaped peaks assigned to the D-->F (J=0,1,2,3,4) transitions. Luminescence from th ... [Appl. Phys. Lett. 93, 211902 (2008)] published Tue Nov 25, 2008.

Control of oxidation and reduction reactions at HfSiO/Si interfaces through N exposure or incorporation

H. Kamada, T. Tanimura, S. Toyoda, H. Kumigashira, M. Oshima et al.
Using synchrotron-radiation photoemission spectroscopy, we have investigated oxidation and reduction reactions of HfSiO(N)/Si gate stack structures annealed in a N or O atmosphere. It is found that both oxidation and reduction reactions can be suppressed by using nitrogen-incorporated HfSiO films in ... [Appl. Phys. Lett. 93, 212903 (2008)] published Tue Nov 25, 2008.

Highly uniform, strongly correlated fluorinated lipid nanodomains embedded in biological membrane models

Jochen Oelke, Andreea Pasc, Achim Wixforth, Oleg Konovalov, and Motomu Tanaka
Synthetic, fluorinated lipids incorporated into phospholipid membranes form highly uniform self-assembled lipid nanodomains. The size of nanodomains beyond optical resolution can quantitatively be determined using grazing-incidence x-ray diffraction. The long-range interaction can reach up to the di ... [Appl. Phys. Lett. 93, 213901 (2008)] published Tue Nov 25, 2008.

Study of electric and magnetic properties of (Bi[sub 0.9]Pb[sub 0.1]) (Fe[sub 0.9]Ti[sub 0.1])O[sub 3] nanomultiferroic system

K. Singh, R. K. Kotnala, and M. Singh
Multiferroic compound (BiPb)(FeTi)O (BPFTO), having particle size of 1525 nm, was synthesized by solution combustion method. BPFTO shows the coexistence of ferroelectricity and magnetism at room temperature. Significant enhancement in magnetic moment with moderate value of the electrical polarizatio ... [Appl. Phys. Lett. 93, 212902 (2008)] published Tue Nov 25, 2008.

A model for debris clouds produced by impact of hypervelocity projectiles on multiplate structures

Qingming Zhang, Renrong Long, Fenglei Huang, Li Chen, and Yuesheng Fu
Hypervelocity impact of spherical and cylindrical projectiles on multipate shields at velocities between 4 and 6 km/s was investigated experimentally. A model was developed to describe the motion of the debris clouds generated. Good agreement was obtained between the experimental and simulation res ... [Appl. Phys. Lett. 93, 211905 (2008)] published Tue Nov 25, 2008.

Microwave absorption in percolating metal-insulator composites

D. T. Zimmerman, J. D. Cardellino, K. T. Cravener, K. R. Feather, N. M. Miskovsky et al.
We measure several electromagnetic properties of tungsten-Teflon composites as a function of metal volume concentration. The electric (E) and magnetic (H) loss tangents at 2.45 GHz and the dc conductivity each exhibits a percolation transition at a different critical value of the metal volume fract ... [Appl. Phys. Lett. 93, 214103 (2008)] published Tue Nov 25, 2008.

Narrow-line coherently combined tapered laser diodes in a Talbot external cavity with a volume Bragg grating

David Paboeuf, Gaelle Lucas-Leclin, Patrick Georges, Nicolas Michel, Michel Krakowski et al.
We present the phase locking of an array of index-guided tapered laser diodes. An external cavity based on the self-imaging Talbot effect has been built. A volume Bragg grating is used as the output coupler to stabilize and narrow the spectrum at 976 nm. A power of 1.7 W is achieved in the in-phas ... [Appl. Phys. Lett. 93, 211102 (2008)] published Tue Nov 25, 2008.

Charge detection in graphene quantum dots

J. Guttinger, C. Stampfer, S. Hellmuller, F. Molitor, T. Ihn et al.
We report measurements on a graphene quantum dot with an integrated graphene charge detector. The quantum dot device consists of a graphene island (diameter of ~200 nm) connected to source and drain contacts via two narrow graphene constrictions. From Coulomb diamond measurements a charging energy ... [Appl. Phys. Lett. 93, 212102 (2008)] published Mon Nov 24, 2008.

An extremely high dielectric constant in bismuth-based pyrochlore multilayer film capacitors combined with percolative structure

Nguyen Duy Cuong, Jun-Ku Ahn, Kyung-Woo Park, Nak-Jin Seong, and Soon-Gil Yoon
The percolative film capacitor structure of Pt/BiMgNbO [BMN(Ar) films deposited at pure argon atmosphere]/Pt was addressed for achievement of a high dielectric constant in the films deposited at room temperature by radio frequency magnetron sputtering. The deterioration of the leakage current charac ... [Appl. Phys. Lett. 93, 212901 (2008)] published Mon Nov 24, 2008.

Similarities in the kinetics of photocrystallization and photodarkening in a-Se

Robert E. Tallman, A. Reznik, B. A. Weinstein, S. D. Baranovskii, and J. A. Rowlands
The onset time of photocrystallization (PC) as a function of temperature in a-Se films designed for avalanche photodetectors is explored using Raman scattering experiments. The PC onset time tau is compared to the time-constant tau for irreversible photodarkening (IPD) studied in earlier work. Both ... [Appl. Phys. Lett. 93, 212103 (2008)] published Mon Nov 24, 2008.

Effects of thermal annealing on noise property and temperature coefficient of resistance of single-walled carbon nanotube films

Rongtao Lu, Guowei Xu, and Judy Z. Wu
The effect of thermal annealing on the electrical transport properties of purified and COOH-functionalized single-walled carbon nanotube (SWCNT) films has been investigated and the correlation between the noise property and temperature coefficient of resistance (TCR) has been derived. Thermal anneal ... [Appl. Phys. Lett. 93, 213101 (2008)] published Mon Nov 24, 2008.

Quantitative coherent diffractive imaging of an integrated circuit at a spatial resolution of 20 nm

Brian Abbey, Garth J. Williams, Mark A. Pfeifer, Jesse N. Clark, Corey T. Putkunz et al.
The complex transmission function of an integrated circuit is reconstructed at 20 nm spatial resolution using coherent diffractive imaging. A quantitative map is made of the exit surface wave emerging from void defects within the circuit interconnect. Assuming a known index of refraction for the sub ... [Appl. Phys. Lett. 93, 214101 (2008)] published Mon Nov 24, 2008.

p-type conduction in nitrogen-doped ZnS nanoribbons

G. D. Yuan, W. J. Zhang, W. F. Zhang, X. Fan, I. Bello et al.
We report reproducible p-type transport properties in nitrogen-doped ZnS nanoribbons (NRs) synthesized by applying ammonia gas as the acceptor source. Field-effect transistors fabricated from individual ZnS NRs revealed the p-type behavior of ZnS NRs and significant enhancement in p-type transport p ... [Appl. Phys. Lett. 93, 213102 (2008)] published Mon Nov 24, 2008.

Pseudogap formation in the metallic state of La[sub 0.7]Sr[sub 0.3]MnO[sub 3] thin films

Udai Raj Singh, Anjan K. Gupta, Goutam Sheet, Venkat Chandrasekhar, H. W. Jang et al.
We report on scanning tunneling microscopy and spectroscopy (STM/S) studies of epitaxial LaSrMnO (LSMO) thin films on a lattice matched (001) LaSrAlTaO substrate for both as-grown and annealed films. In contrast to the as-grown films, the films annealed at 800 degrees C in air show atomic terraces ... [Appl. Phys. Lett. 93, 212503 (2008)] published Mon Nov 24, 2008.

Photoluminescence of confined electron-hole plasma in core-shell silicon/silicon oxide nanowires

O. Demichel, F. Oehler, P. Noe, V. Calvo, N. Pauc et al.
We study by low temperature photoluminescence measurements the electronic states of silicon nanowires obtained by copper catalyzed chemical vapor deposition and compare them with those of wires made by etching silicon on the insulator structure. Thermal oxidation of nanowires appears to be absolutel ... [Appl. Phys. Lett. 93, 213104 (2008)] published Mon Nov 24, 2008.

Energy barriers at interfaces of (100)GaAs with atomic layer deposited Al[sub 2]O[sub 3] and HfO[sub 2]

V. V. Afanas'ev, M. Badylevich, A. Stesmans, G. Brammertz, A. Delabie et al.
Band alignment at the interfaces of (100)GaAs with AlO and HfO grown using atomic layer deposition is determined using internal photoemission and photoconductivity measurements. Though the inferred conduction and valence band offsets for both insulators were found to be close to or larger than 2 eV, ... [Appl. Phys. Lett. 93, 212104 (2008)] published Mon Nov 24, 2008.

The investigation of capture/emission mechanism in high-k gate dielectric soft breakdown by gate current random telegraph noise approach

Steve S. Chung and C. M. Chang
In this paper, the trapping/detrapping in high-k gate dielectrics has been analyzed by gate current random telegraph noise (I) measurement. Gate current is suppressed when traps capture electrons and recovers for empty traps. By statistically extracting capture and emission times, we can understand ... [Appl. Phys. Lett. 93, 213502 (2008)] published Mon Nov 24, 2008.

Narrow-band deep-ultraviolet light emitting device using Al[sub 1 - x]Gd[sub x]N

Takashi Kita, Shinya Kitayama, Masashi Kawamura, Osamu Wada, Yoshitaka Chigi et al.
We demonstrated mercury-free narrow-band deep-ultraviolet luminescence from field-emission devices with AlGdN thin films. The AlGdN thin films were grown on fused silica substrates by a radio frequency reactive magnetron sputtering method. The deposited film shows a strong c-axis preferential orient ... [Appl. Phys. Lett. 93, 211901 (2008)] published Mon Nov 24, 2008.

Ferromagnetic spin-correlations in strained LaCoO[sub 3] thin films

J. W. Freeland, J. X. Ma, and J. Shi
We present an element-resolved study of the valence and magnetic properties of LaCoO thin films grown via pulsed laser deposition. The Co L edge x-ray absorption shows that ferromagnetic (FM) order arises from a slight hole doping of the system presumably due to nonstoichiometry, which in the bulk s ... [Appl. Phys. Lett. 93, 212501 (2008)] published Mon Nov 24, 2008.

Properties of excited xenon atoms in an alternating current plasma display panel

Han S. Uhm, Phil Y. Oh, and Eun H. Choi
The properties of excited xenon atoms in the discharge cells of a plasma display panel are investigated by measuring the excited atom density via laser absorption spectroscopy. The density of the excited xenon atoms in the metastable state increases from zero, reaches its peak, and decreases with ti ... [Appl. Phys. Lett. 93, 211501 (2008)] published Mon Nov 24, 2008.

Evaluation of capacitance-voltage characteristic and memory window of metal-ferroelectric-insulator-silicon capacitors

X. J. Zheng, J. Sun, J. J. Zhang, M. H. Tang, and W. Li
It is recognized that the conventional model for metal-ferroelectric-insulator-silicon (MFIS) capacitor is always not consistent with the experimental observation very well due to negligence of the history-dependent electric field effect. In this letter, combining the switching physics of ferroelect ... [Appl. Phys. Lett. 93, 213501 (2008)] published Mon Nov 24, 2008.

Optical nanolithography using a scanning near-field probe with an integrated light source

James W. Kingsley, Sumon K. Ray, Ali M. Adawi, Graham J. Leggett, and David G. Lidzey
An ultracompact near-field optical probe is described that is based on a single, integrated assembly consisting of a gallium nitride (GaN) light-emitting diode (LED), a microlens, and a cantilever assembly containing a hollow pyramidal probe with a subwavelength aperture at its apex. The LED emits u ... [Appl. Phys. Lett. 93, 213103 (2008)] published Mon Nov 24, 2008.

Dynamic colloidal sorting on a magnetic bubble lattice

Pietro Tierno, Alejandro Soba, Tom H. Johansen, and Francesc Sagues
We use a uniaxial garnet film with a magnetic bubble lattice to sort paramagnetic colloidal particles with different diameters, i.e., 1.0 and 2.8 [mu]m. We apply an external magnetic field which precesses around an axis normal to the film with a frequency Omega=62.8 s and intensity 3120 A/m

High-quality quantum point contact in two-dimensional GaAs (311)A hole system

J. Shabani, J. R. Petta, and M. Shayegan
We studied ballistic transport across a quantum point contact (QPC) defined in a high-quality GaAs (311)A two-dimensional hole system using shallow etching and top gating. The QPC conductance exhibits up to 11 quantized plateaus. The ballistic one-dimensional subbands are tuned by changing the later ... [Appl. Phys. Lett. 93, 212101 (2008)] published Mon Nov 24, 2008.

High program efficiency of p-type floating gate in n-channel split-gate embedded flash memory

Hung-Sheng Shih, Shang-Wei Fang, An-Chi Kang, Ya-Chin King, and Chrong-Jung Lin
This work proposes a novel p-type boron-doped floating gate for n-channel split-gate flash memory. A lower program voltage, with a programming time of 7 [mu]s, results in five times of the conventional source-side injection programming efficiency, a 5% wider program/erase window, and more reliable ... [Appl. Phys. Lett. 93, 213503 (2008)] published Mon Nov 24, 2008.

Bias-dependent rectifying properties of n-n manganite heterojunctions La[sub 1 - x]Ca[sub x]MnO[sub 3]/SrTiO[sub 3]:Nb (x = 0.65--1)

W. M. Lu, J. R. Sun, D. J. Wang, Y. W. Xie, S. Liang et al.
The transport property of n-n type manganite heterojunctions, composed of LaCaMnO films (x=0.6, 0.75, 0.85, and 1) and 0.05 wt % Nb-doped SrTiO, has been experimentally studied. Different from p-n junctions, the rectifying behavior of which is either thermionic emission/diffusion-dominated or tunne ... [Appl. Phys. Lett. 93, 212502 (2008)] published Mon Nov 24, 2008.

Electromigration-induced shock waves on metal thin films

R. Mark Bradley
It is shown that surface electromigration can produce shock waves that retain their form as they propagate on the edge of a single-crystal metal thin film. We explain why these shocks form, determine their velocity, and find their internal structure. If two shocks are present initially, they collide ... [Appl. Phys. Lett. 93, 213105 (2008)] published Mon Nov 24, 2008.

Carrier concentration dependence of terahertz transmission on conducting ZnO films

Guohong Ma, Dong Li, Hong Ma, Jie Shen, Chenguo Wu et al.
With the dc reactive magnetron sputtering method, conducting ZnO thin films with different carrier concentrations on glass substrate were fabricated. The dielectric responses of the ZnO films are characterized with terahertz time-domain spectroscopy. Frequency-dependent conductivity, power absorptio ... [Appl. Phys. Lett. 93, 211101 (2008)] published Mon Nov 24, 2008.

Why so strong for the lotus leaf?

Zhiguang Guo, Weimin Liu, and Bao-Lian Su
The authors discussed the potential reasons why the lotus leaf is so strong by means of scanning electron microscopy (SEM). The results showed that the good mechanical properties of lotus leaf should be attributed to its architecture, such as paralleled microtubes structure, umbrellalike structure, ... [Appl. Phys. Lett. 93, 201909 (2008)] published Fri Nov 21, 2008.

Nanocrystalline diamond lateral vacuum microtriode

K. Subramanian, W. P. Kang, and J. L. Davidson
A vacuum field emission microtriode in lateral configuration utilizing nanocrystalline diamond is presented. The nanodiamond lateral triode is a completely integrated device comprising a fingerlike emitter geometry with an ~15 nm tip radius of curvature, built-in gate, and anode with gate-cathode s ... [Appl. Phys. Lett. 93, 203511 (2008)] published Fri Nov 21, 2008.

Pseudoferroelectricity: A possible scenario for doped ZnO

Alexander K. Tagantsev
A phenomenological Landau-theory model, where a crystal on cooling from a state with polar symmetry exhibits a maximum of dielectric permittivity and polarization-field hysteresis loops, is offered. The model is equivalent to that of a true ferroelectric in a weak external dc bias. Permittivity maxi ... [Appl. Phys. Lett. 93, 202905 (2008)] published Fri Nov 21, 2008.

Controlling multidomain states to enable sub-10-nm magnetic force microscopy

Nissim Amos, Rabee Ikkawi, Robert Haddon, Dmitri Litvinov, and Sakhrat Khizroev
The letter reports experimental data to demonstrate magnetic force microscopy (MFM) with sub-10-nm resolution under ambient conditions. To achieve this record high resolution, multidomain states in a nanomagnetic probe were controlled. Two demagnetized (multidomain) FePt (45/55) films sputtered on a ... [Appl. Phys. Lett. 93, 203116 (2008)] published Fri Nov 21, 2008.

Ponderomotive electron acceleration by polarization-gated surface-enhanced optical fields

Peifen Lu, Jian Wu, Hongxing Qi, and Heping Zeng
We study ponderomotive electron acceleration with polarization-gated surface-plasmon-resonance enhanced optical fields excited by two counter-incident femtosecond laser pulses. Such a polarization-gated excitation scheme creates an intense linearly polarized high-gradient evanescent field for electr ... [Appl. Phys. Lett. 93, 201108 (2008)] published Fri Nov 21, 2008.

Characterizing the global dispersion of carbon nanotubes in ceramic matrix nanocomposites

Orsolya Koszor, Levente Tapaszto, Marton Marko, and Csaba Balazsi
The dispersion of single-walled carbon nanotubes in silicon nitride ceramic matrices has been investigated by small angle neutron scattering experiments. In contrast to electron microscopy investigations of fracture surfaces, neutron scattering measurements provide information on the bulk dispersion ... [Appl. Phys. Lett. 93, 201910 (2008)] published Fri Nov 21, 2008.

Bias mediated tuning of the detection wavelength in asymmetrical quantum dots-in-a-well infrared photodetectors

L. Hoglund, P. O. Holtz, H. Pettersson, C. Asplund, Q. Wang et al.
Bias-mediated tuning of the detection wavelength within the infrared wavelength region is demonstrated for quantum dots-in-a-well and dots-on-a-well infrared photodetectors. By positioning the InAs quantum dot layer asymmetrically in an 8 nm wide InGaAs/GaAs quantum well, a shift in the peak detecti ... [Appl. Phys. Lett. 93, 203512 (2008)] published Fri Nov 21, 2008.

Temperature dependent photoluminescence from ZnO nanowires and nanosheets on brass substrate

Xiuquan Gu, Kaifu Huo, Guixiang Qian, Jijiang Fu, and Paul K. Chu
The temperature-dependent optical properties of ZnO nanosheets and nanowires fabricated on conductive brass substrates with different surface-to-volume ratios and morphologies are investigated. The near band edge and deep-level emission mechanisms are studied. The blueshifted donor bound exciton D X ... [Appl. Phys. Lett. 93, 203117 (2008)] published Fri Nov 21, 2008.

Current collapse in AlGaN/GaN transistors studied using time-resolved Raman thermography

R. J. T. Simms, J. W. Pomeroy, M. J. Uren, T. Martin, and M. Kuball
Current collapse in AlGaN/GaN high electron mobility transistors was investigated using time-resolved Raman thermography. The virtual-gate mechanism was visualized by changes in the device temperature distribution, illustrating an effective gate lengthening up to 0.6 um. Two devices with different l ... [Appl. Phys. Lett. 93, 203510 (2008)] published Thu Nov 20, 2008.

Segregation of tungsten at gamma[sup [prime]](L1[sub 2])/gamma(fcc) interfaces in a Ni-based superalloy: An atom-probe tomographic and first-principles study

Yaron Amouyal, Zugang Mao, and David N. Seidman
gamma(fcc)/gamma(L1) heterophase interfaces in a Ni-based superalloy are investigated using atom-probe tomography and first-principles calculations. Flat {100} interfaces exhibit a confined (nonmonotonic) Gibbsian interfacial excess of tungsten, Gamma=1.20.2 nm, corresponding to a 5 mJ m decrease ... [Appl. Phys. Lett. 93, 201905 (2008)] published Thu Nov 20, 2008.

Selective-hydrogen sensing at room temperature with Pt-coated InN nanobelts

Wantae Lim, J. S. Wright, B. P. Gila, S. J. Pearton, F. Ren et al.
The hydrogen sensing characteristics of multiple InN nanobelts grown by metalorganic chemical vapor deposition were investigated. Pt-coated InN sensors could selectively detect hydrogen at the tens of ppm level at 25 degrees C, while uncoated InN showed no detectable change in current when exposed ... [Appl. Phys. Lett. 93, 202109 (2008)] published Thu Nov 20, 2008.

Influence of a bimodal eutectic structure on the plasticity of a (Ti[sub 70.5]Fe[sub 29.5])[sub 91]Sn[sub 9] ultrafine composite

J. H. Han, K. B. Kim, S. Yi, J. M. Park, D. H. Kim et al.
Systematic investigations on the microstructural evolution of a bimodal eutectic (TiFe)Sn ultrafine composite containing TiSn dendrites upon compression reveal that local deformation of the dendrites dominates the early stage of deformation with a plastic strain of epsilon=5.8%. After further deform ... [Appl. Phys. Lett. 93, 201906 (2008)] published Thu Nov 20, 2008.

Origin of unusual rapid oxidation process for ultrathin oxidation (< 2 nm) of silicon

H. Cui, C. X. Wang, G. W. Yang, and D. Jiang
We propose a kinetic model to reveal the origin of unusual rapid oxidation behavior for the ultrathin (<2 nm) oxidation of silicon demonstrated by [Enta et al., Appl. Phys. Lett. 92, 012110 (2008)] by considering the space-charge drift of O ions and the intrinsic concentration gradient diffusion of ... [Appl. Phys. Lett. 93, 203113 (2008)] published Thu Nov 20, 2008.

Tuning the electrical switching of polymer/fullerene nanocomposite thin film devices by control of morphology

Ari Laiho, Himadri S. Majumdar, Jayanta K. Baral, Fredrik Jansson, Ronald Osterbacka et al.
The working principles of thin film organic memory devices remain debated and tunability has been less presented. We show that the nanostructure of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and polystyrene (PS) allows facile tuning of switching behavior for low PCBM concentrations upon annea ... [Appl. Phys. Lett. 93, 203309 (2008)] published Thu Nov 20, 2008.

First-principles studies of water adsorption on graphene: The role of the substrate

Tim O. Wehling, Alexander I. Lichtenstein, and Mikhail I. Katsnelson
We investigate the electronic properties of graphene upon water adsorption and study the influence of the SiO substrate in this context using density functional calculations. Perfect suspended graphene is rather insensitive to HO adsorbates, as doping requires highly oriented HO clusters. For graphe ... [Appl. Phys. Lett. 93, 202110 (2008)] published Thu Nov 20, 2008.

High shear rheology of shear banding fluids in microchannels

Philippe Nghe, Guillaume Degre, Patrick Tabeling, and Armand Ajdari
We characterize heterogeneous flows of a wormlike micelles solution in microchannels. Combining a pressure resistant microfabrication technology and a performant particle image velocimetry setup, we succeed in determining the nonlinear rheology of this fluid over 4 decades in shear rate and in parti ... [Appl. Phys. Lett. 93, 204102 (2008)] published Thu Nov 20, 2008.

GaAs/AlGaAs quantum dot laser fabricated on GaAs (311)A substrate by droplet epitaxy

T. Mano, T. Kuroda, K. Mitsuishi, Y. Nakayama, T. Noda et al.
We have demonstrated photopumped laser action of self-assembled GaAs/AlGaAs quantum dots (QDs) grown on GaAs (311)A substrate by droplet epitaxy. Due to the short migration distance of Ga adatoms across the (311)A surface, high-density QDs were created with high uniformity. The QDs exhibited a narro ... [Appl. Phys. Lett. 93, 203110 (2008)] published Thu Nov 20, 2008.

Controlled transport of magnetic particles using soft magnetic patterns

Richard S. Conroy, Gary Zabow, John Moreland, and Alan P. Koretsky
Inspired by magnetic bubble memory technology, we demonstrate the temporal and spatial manipulation of superparamagnetic beads guided by soft magnetic patterns in a rotating magnetic field. Soft magnetic structures allow complex and repetitive tasks to be performed. As a demonstration, we show cycli ... [Appl. Phys. Lett. 93, 203901 (2008)] published Thu Nov 20, 2008.

Direct observation of changes to domain wall structures in magnetic nanowires of varying width

K. J. O'Shea, S. McVitie, J. N. Chapman, and J. M. R. Weaver
Lorentz microscopy has been used to explore the structure variation of domain walls in thin Permalloy nanowires in the vicinity of symmetric triangular antinotches. The antinotches present a complex potential landscape to domain walls. Walls can be trapped in front of, partly enter, or be trapped in ... [Appl. Phys. Lett. 93, 202505 (2008)] published Thu Nov 20, 2008.

Valence band offset of the ZnO/AlN heterojunction determined by x-ray photoemission spectroscopy

T. D. Veal, P. D. C. King, S. A. Hatfield, L. R. Bailey, C. F. McConville et al.
The valence band offset of ZnO/AlN heterojunctions is determined by high resolution x-ray photoemission spectroscopy. The valence band of ZnO is found to be 0.430.17 eV below that of AlN. Together with the resulting conduction band offset of 3.290.20 eV, this indicates that a type-II (staggered) b ... [Appl. Phys. Lett. 93, 202108 (2008)] published Thu Nov 20, 2008.

Enhancing single-molecule photostability by optical feedback from quantum jump detection

V. Jacques, J. D. Murray, F. Marquier, D. Chauvat, F. Grosshans et al.
We report an optical technique that yields an enhancement of single-molecule photostability by greatly suppressing photobleaching pathways which involve photoexcitation from the triplet state. This is accomplished by dynamically switching off the excitation laser when a quantum jump of the molecule ... [Appl. Phys. Lett. 93, 203307 (2008)] published Thu Nov 20, 2008.

Reconfiguration of microring resonators by liquid adhesion

C. A. Barrios, M. Holgado, O. Guarneros, K. B. Gylfason, B. Sanchez et al.
We present a procedure to reconfigure microring resonators based on liquid surface adhesion. Droplets of organic solvents were deposited over SiN/SiO strip- and slot-waveguide ring resonators, and the transmission spectra were measured several hours after the evaporation of the droplets at room temp ... [Appl. Phys. Lett. 93, 203114 (2008)] published Thu Nov 20, 2008.

Bloch-point-mediated magnetic antivortex core reversal triggered by sudden excitation of a suprathreshold spin-polarized current

X. J. Xing, Y. P. Yu, S. X. Wu, L. M. Xu, and S. W. Li
We report on spin dynamics of single magnetic antivortices driven by sudden excitation of a spin-polarized direct current. Using micromagnetic simulations, we find that there is a critical current density where spin dynamics transition occurs. Above the critical value, the core is switched on a time ... [Appl. Phys. Lett. 93, 202507 (2008)] published Thu Nov 20, 2008.

Nanomechanical thermal analysis of electrospun polymer fibers

Wei Wang, Andrew J. Bushby, and Asa H. Barber
Thermomechanical properties of individual electrospun semicrystalline polyethylene oxide (PEO) fibers were measured using atomic force microscopy based indentation. Fibers showed a higher elastic modulus than corresponding films despite a lower crystallinity, indicating significant molecular alignme ... [Appl. Phys. Lett. 93, 201907 (2008)] published Thu Nov 20, 2008.

Quantitative scanning thermal microscopy using double scan technique

Kyeongtae Kim, Jaehoon Chung, Jongbo Won, Ohmyoung Kwon, Joon Sik Lee et al.
Although scanning thermal microscope has shown the highest spatial resolution in local temperature and thermophysical property measurement, its usefulness has been severely limited due to difficulties in quantitative measurement. We propose a double scan technique that measures temperature only from ... [Appl. Phys. Lett. 93, 203115 (2008)] published Thu Nov 20, 2008.

Doping of Ge--Si[sub x]Ge[sub 1 - x] core-shell nanowires using low energy ion implantation

Junghyo Nah, K. Varahramyan, E.-S. Liu, S. K. Banerjee, and E. Tutuc
We investigate the doping of germanium (Ge)silicon germanium (SiGe) core-shell nanowires (NWs) by low energy (3 keV) boron (B) ion implantation. GeSiGe core-shell NWs were implanted with B atoms at different doses from 1 x 10 to 1 x 10 cm, and subsequently annealed for dopant activation. Using four ... [Appl. Phys. Lett. 93, 203108 (2008)] published Thu Nov 20, 2008.

Controlled electron injection into laser wakefields with a perpendicular injection laser pulse

W.-M. Wang, Z.-M. Sheng, and J. Zhang
Electron injection into laser wakefields for acceleration by two orthogonally directed laser pulses is investigated theoretically. It is found that efficient injection occurs provided the two pulses are collinearly polarized, even if the injection pulse is much weaker than the pump pulse driving wak ... [Appl. Phys. Lett. 93, 201502 (2008)] published Thu Nov 20, 2008.

Polarity driven formation of InAs/GaAs hierarchical nanowire heterostructures

Mohanchand Paladugu, Jin Zou, Ya-Nan Guo, Xin Zhang, Hannah J. Joyce et al.
The structural and morphological characteristics of InAs/GaAs radial nanowire heterostructures were investigated using transmission electron microscopy. It has been found that the radial growth of InAs was preferentially initiated on the {112} sidewalls of GaAs nanowires. This preferential depositio ... [Appl. Phys. Lett. 93, 201908 (2008)] published Thu Nov 20, 2008.

Phonon-assisted ultraviolet anti-Stokes photoluminescence from GaN film grown on Si (111) substrate

Suvranta K. Tripathy, Guibao Xu, Xiaodong Mu, Yujie J. Ding, Muhammad Jamil et al.
Phonon-assisted anti-Stokes photoluminescence (ASPL) in the ultraviolet region has been observed in the GaN film grown on a Si (111) substrate. The ASPL peaks are observable only at sufficiently low temperatures. In addition, even if the photon energy is [approximate]318 meV below the transition en ... [Appl. Phys. Lett. 93, 201107 (2008)] published Thu Nov 20, 2008.

Magnetoresistance studies on Co/AlO[sub X]/Au and Co/AlO[sub X]/Ni/Au tunnel structures

R. S. Liu, C. M. Canali, L. Samuelson, and H. Pettersson
We report on magnetoresistance (MR) studies on Co/AlO/Au and Co/AlO/Ni/Au magnetic tunnel junctions. In spite of the fact that the difference between the two samples is merely a 3 nm thick Ni layer, there is a sharp contrast in MR behavior indicating that the electronic structure at the interface b ... [Appl. Phys. Lett. 93, 203107 (2008)] published Thu Nov 20, 2008.

Self-aligned flexible all-polymer transistor: Ultraviolet printing

Hyewon Kang, Tae-il Kim, and Hong H. Lee
Flexible all-polymer transistor has received much attention because it is needed for the unique area of flexible circuits and displays, and the solution processing allowed with polymers would enable low-cost production. In this work, we introduce and utilize ultraviolet (UV) printing technique for t ... [Appl. Phys. Lett. 93, 203308 (2008)] published Thu Nov 20, 2008.

Influence of strong electric fields on the growth, modification, and destruction of thin oxide films at the titanium surface

S. A. Kovalevskii, F. I. Dalidchik, M. V. Grishin, and A. K. Gatin
The influence of strong electric fields (~10 V/cm) on the growth, modification, and destruction of thin oxide films at the metal surfaces are studied for a titanium tip of a scanning tunneling microscope (STM) oxidized in oxygen at different tip potentials. The spectroscopic measurements show that, ... [Appl. Phys. Lett. 93, 203112 (2008)] published Thu Nov 20, 2008.

Charge transport dynamics of polymer solar cells under operating conditions: Influence of trap filling

Christopher R. McNeill and Neil C. Greenham
The authors report time-of-flight measurements on photovoltaic blends of poly(3-hexylthiophene) and poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2,2-diyl) (F8TBT). Through the use of an additional illumination source to provide a background current dens ... [Appl. Phys. Lett. 93, 203310 (2008)] published Thu Nov 20, 2008.

Coherent manipulation of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As with successive optical pumping

Y. Hashimoto and H. Munekata
We report the dynamic control of magnetization precession by light alone. A ferromagnetic (Ga,Mn)As epilayer was used for experiments. Amplitude of precession was modulated to a large extent by tuning the time interval between two successive optical pump pulses, which induced torques on magnetizatio ... [Appl. Phys. Lett. 93, 202506 (2008)] published Thu Nov 20, 2008.

Electrical characterization of gold island films: A route to control of nanoparticle deposition

A. Lassesson, S. A. Brown, J. van Lith, and M. Schulze
The evaporation of gold onto SiN or SiO leads to the formation of nanoscale islands separated by tunneling barriers. As the deposited thickness of Au increases, there is a linear increase in island size and an exponential decrease in film resistance, resulting from coalescence of neighboring islands ... [Appl. Phys. Lett. 93, 203111 (2008)] published Thu Nov 20, 2008.

Directional properties of hard x-ray sources generated by tightly focused ultrafast laser pulses

Bixue Hou, Aghapi Mordovanakis, James Easter, Karl Krushelnick, and John A. Nees
Directional properties of ultrafast laser-based hard x-ray sources are experimentally studied using tightly focused approximately millijoule laser pulses incident on a bulk Mo target. Energy distributions of Kalpha and total x rays, as well as source-size distributions are directionally resolved in ... [Appl. Phys. Lett. 93, 201503 (2008)] published Thu Nov 20, 2008.

Integration of vertical InAs nanowire arrays on insulator-on-silicon for electrical isolation

Shadi A. Dayeh, Peng Chen, Yi Jing, Edward T. Yu, S. S. Lau et al.
Vertical and electrically isolated InAs nanowires (NWs) are integrated with Si in a technique that bypasses structural defects and transport barriers at the SiIIIV NW interface. Smart-cut[registered sign] technique is used to transfer a thin InAs layer onto SiO/Si and is subsequently used for ordere ... [Appl. Phys. Lett. 93, 203109 (2008)] published Thu Nov 20, 2008.

Fabrication of submicron structures in nanoparticle/polymer composite by holographic lithography and reactive ion etching

A. Ping Zhang, Sailing He, Kyoung Tae Kim, Yong-Kyu Yoon, Ryszard Burzynski et al.
We report on the fabrication of nanoparticle/polymer submicron structures by combining holographic lithography and reactive ion etching. Silica nanoparticles are uniformly dispersed in a (SU8) polymer matrix at a high concentration, and in situ polymerization (cross-linking) is used to form a nanopa ... [Appl. Phys. Lett. 93, 203509 (2008)] published Thu Nov 20, 2008.

Epitaxial growth of high mobility Cu[sub 2]O thin films and application to p-channel thin film transistor

Kosuke Matsuzaki, Kenji Nomura, Hiroshi Yanagi, Toshio Kamiya, Masahiro Hirano et al.
CuO epitaxial films were grown for high mobility p-channel oxide thin-film transistors (TFTs). The use of a (110) MgO surface and fine tuning of a growth condition produced single phase epitaxial films with hole Hall mobilities ~90 cm V s comparable to those of single crystals (~100 cm V s). TFTs ... [Appl. Phys. Lett. 93, 202107 (2008)] published Thu Nov 20, 2008.

Interface control and leakage current conduction mechanism in HfO[sub 2] film prepared by pulsed laser deposition

Hao Wang, Y. Wang, J. Zhang, C. Ye, H. B. Wang et al.
The N atmosphere postannealing is introduced to improve the interfacial quality and the dielectric properties of HfO films prepared by pulsed laser deposition. The disappearance of interface layer between HfO film and Si substrate and the decrease of leakage current densities after annealing are fur ... [Appl. Phys. Lett. 93, 202904 (2008)] published Thu Nov 20, 2008.

Experimental demonstration of tunable negative phase velocity and negative refraction in a ferromagnetic/ferroelectric composite metamaterial

Hongjie Zhao, Lei Kang, Ji Zhou, Qian Zhao, Longtu Li et al.
A tunable left-handed transmission is demonstrated experimentally in a ferromagnetic/ferroelectric composite metamaterial (CMM) consisting of an array of yttrium iron garnet (YIG) rods combined with barium strontium titanate (BST) rods. We observed a passband in the CMM within the overlap of the sto ... [Appl. Phys. Lett. 93, 201106 (2008)] published Thu Nov 20, 2008.

Dynamic-gate operation in nanoelectronic amplifiers due to reduced screening

L. Worschech, D. Hartmann, and A. Forchel
Semiconductor nanostructures in shape of a Y were patterned lithographically in a two-dimensional electron gas. One of the branches was pinched off, so it can act as a gate for the other branch. Such nanoelectronic amplifiers show switching voltages smaller than the thermal limit and tunable bistabi ... [Appl. Phys. Lett. 93, 203105 (2008)] published Wed Nov 19, 2008.

Ab initio investigation on oxygen defect clusters in UO[sub 2 + x]

Hua Y. Geng, Ying Chen, Yasunori Kaneta, and Motoyasu Kinoshita
Oxygen defect clustering in uranium dioxide had been indicated in powder neutron diffraction measurements, and an empirical clustering mechanism had been proposed to explain the data. However, using first-principles LSDA+U calculations, we find that this empirical model, in fact, cannot work. A more ... [Appl. Phys. Lett. 93, 201903 (2008)] published Wed Nov 19, 2008.

Enhanced Jahn--Teller distortion in the orthorhombic phase of La[sub 0.15]Ca[sub 0.85]MnO[sub 3] and Y[sub 0.15]Ca[sub 0.85]MnO[sub 3]

P. Tong, Bongju Kim, Daeyoung Kwon, Bog G. Kim, G. Y. Ahn et al.
We report the results of neutron powder diffraction experiments on LaCaMnO and YCaMnO. After an incomplete orthorhombic-monoclinic phase transition, the residual orthorhombic phase undergoes an enhancement of JahnTeller distortion of MnO octahedra. The degree of JahnTeller distortion is strongly inf ... [Appl. Phys. Lett. 93, 202504 (2008)] published Wed Nov 19, 2008.

Universal scaling in wildfire fractal propagation

Bernard Porterie, Ahmed Kaiss, Jean-Pierre Clerc, Lotfi Zekri, and Nouredine Zekri
A small-world network model is proposed to predict wildfire behavior near critical propagation conditions. It includes long-range connections due to flame radiation and a weighting procedure based on times of degradation and combustion of vegetation. Scaling laws are found universal near the propaga ... [Appl. Phys. Lett. 93, 204101 (2008)] published Wed Nov 19, 2008.

Half-cycle atomic layer deposition reaction studies of Al[sub 2]O[sub 3] on In[sub 0.2]Ga[sub 0.8]As (100) surfaces

M. Milojevic, F. S. Aguirre-Tostado, C. L. Hinkle, H. C. Kim, E. M. Vogel et al.
The reduction in IIIV interfacial oxides by atomic layer deposition of AlO on InGaAs is studied by interrupting the deposition following individual trimethyl aluminum (TMA) and water steps (half cycles) and interrogation of the resultant surface reactions using in situ monochromatic x-ray photoelect ... [Appl. Phys. Lett. 93, 202902 (2008)] published Wed Nov 19, 2008.

Magnetic steering of a helicon double layer thruster

C. Charles, R. W. Boswell, W. Cox, R. Laine, and P. MacLellan
The ion beam generated by a helicon double layer has been electrically steered up to 20 degrees off axis by using a solenoid placed normal to the two axial solenoids of the helicon plasma source without significantly changing the beam exhaust velocity. ... [Appl. Phys. Lett. 93, 201501 (2008)] published Wed Nov 19, 2008.

Erratum: ``The role of the beta-phase content on the stimulated emission of poly(9,9-dioctylfluorene) thin films'' [Appl. Phys. Lett. [bold 93], 023308 (2008)]

M. Anni
... [Appl. Phys. Lett. 93, 209902 (2008)] published Wed Nov 19, 2008.

Directional enhanced acoustic radiation caused by a point cavity in a finite-size two-dimensional phononic crystal

Feng-Chia Hsu, Tsung-Tsong Wu, Jin-Chen Hsu, and Jia-Hong Sun
In this letter, we present results of a study on the directional enhanced radiation generated by a point resonant cavity operating at the band-gap frequency of a two-dimensional finite-size phononic crystal. We find that the directive radiation for operating frequency within the band gap comes from ... [Appl. Phys. Lett. 93, 201904 (2008)] published Wed Nov 19, 2008.

Diffusion of atmospheric gases into barrier-layer sealed organic light emitting diodes

Prashant Mandlik, Lin Han, Sigurd Wagner, Jeff A. Silvernail, Rui-Qing Ma et al.
Organic light emitting diodes (OLEDs) are protected from the atmosphere with a barrier layer. Even when this permeation barrier is hermetic, dark spots still may grow and dark sheets may extend into the OLED. These grow by diffusion from the atmosphere along the interfaces between the barrier layer ... [Appl. Phys. Lett. 93, 203306 (2008)] published Wed Nov 19, 2008.

Multiple pulse thermal damage thresholds of materials for x-ray free electron laser optics investigated with an ultraviolet laser

Stefan P. Hau-Riege, Richard A. London, Richard M. Bionta, Regina Soufli, Dmitri Ryutov et al.
Optical elements to be used for x-ray free electron lasers (XFELs) must withstand multiple high-fluence pulses. We have used an ultraviolet laser to study the damage of two candidate materials, crystalline Si and BC-coated Si, emulating the temperature profile expected to occur in optics exposed to ... [Appl. Phys. Lett. 93, 201105 (2008)] published Wed Nov 19, 2008.

Codoping of boron and phosphorus in silicon nanowires synthesized by laser ablation

N. Fukata, M. Mitome, Y. Bando, M. Seoka, S. Matsushita et al.
Codoping of boron (B) and phosphorus (P) atoms was performed during the synthesis of silicon nanowires (SiNWs) by laser ablation. The observation of a local vibrational mode of B clearly showed B doping in codoped SiNWs, while Fano broadening due to heavy B doping disappeared, indicating compensatio ... [Appl. Phys. Lett. 93, 203106 (2008)] published Wed Nov 19, 2008.

Achieving a low interfacial density of states in atomic layer deposited Al[sub 2]O[sub 3] on In[sub 0.53]Ga[sub 0.47]As

H. C. Chiu, L. T. Tung, Y. H. Chang, Y. J. Lee, C. C. Chang et al.
Atomic-layer-deposited AlO on InGaAs with short air exposure between the oxide and semiconductor deposition has enabled the demonstration of nearly ideal frequency-dependent and quasistatic capacitance-voltage (C-V) characteristics. The excellent quasistatic C-V characteristics indicate a high effic ... [Appl. Phys. Lett. 93, 202903 (2008)] published Wed Nov 19, 2008.

Polarization-induced two-dimensional electron gases in ZnMgO/ZnO heterostructures

H. Tampo, H. Shibata, K. Maejima, A. Yamada, K. Matsubara et al.
Both the formation mechanism and the origin of the two-dimensional electron gas (2DEG) in ZnMgO/ZnO heterostructures have been investigated. The 2DEG in the heterostructures was confirmed to originate from polarization-induced charge and was found to be dominant for transport at low temperatures as ... [Appl. Phys. Lett. 93, 202104 (2008)] published Tue Nov 18, 2008.

Improving light output power of InGaN-based light emitting diodes with pattern-nanoporous p-type GaN:Mg surfaces

Chung Chieh Yang, Chia Feng Lin, Chun Min Lin, Cheng Chien Chang, Kuei Ting Chen et al.
InGaN-based light emitting diodes (LEDs) with a top pattern-nanoporous p-type GaN:Mg surface were fabricated by using a photoelectrochemical (PEC) process. The peak wavelengths of electroluminescence (EL) and operating voltages were measured as 461.2 nm (3.1 V), 459.6 nm (9.2 V), and 460.1 nm (3.3 V ... [Appl. Phys. Lett. 93, 203103 (2008)] published Tue Nov 18, 2008.

Alleviation of Fermi-level pinning effect on metal/germanium interface by insertion of an ultrathin aluminum oxide

Yi Zhou, Masaaki Ogawa, Xinhai Han, and Kang L. Wang
Due to the strong Fermi-level pinning close to the germanium (Ge) valence band edge, all metal/p-type Ge contacts show Ohmic characteristics, while metal/n-type Ge contacts exhibit rectifying behaviors. In this paper, we report a simple method to alleviate this Fermi-level pinning effect by insertin ... [Appl. Phys. Lett. 93, 202105 (2008)] published Tue Nov 18, 2008.

Thickness inhomogenities in the organometallic chemical vapor deposition of GaP

X. Liu and D. E. Aspnes
We analyze exponential lateral-thickness variations observed in the growth of GaP on (001) GaAs, thermally generated SiO, (001) Si, and nanoscopically roughened Si surfaces by organometallic chemical vapor deposition, using as a reference the polycrystalline GaP deposited on the Mo susceptor surroun ... [Appl. Phys. Lett. 93, 203104 (2008)] published Tue Nov 18, 2008.

Comparison of the effects of Ar and H[sub 2] plasmas on the performance of homojunctioned amorphous indium gallium zinc oxide thin film transistors

Byung Du Ahn, Hyun Soo Shin, Hyun Jae Kim, Jin-Seong Park, and Jae Kyeong Jeong
We proposed a homojunctioned amorphous InGaZnO (a-IGZO) thin film transistor (TFT) and compared its performance to that of a conventional structured TFT. The source/drain regions were formed in the a-IGZO channel layer using Ar and H plasma treatments, respectively. Hydrogen itself was found to act ... [Appl. Phys. Lett. 93, 203506 (2008)] published Tue Nov 18, 2008.

A sensor circuit using reference-based conductance switching in organic electrochemical transistors

Per-Olof Svensson, David Nilsson, Robert Forchheimer, and Magnus Berggren
Using organic electrochemical transistors as sensors, the sample-receptor reaction often induces moderate changes only in the drain current dynamics as the gate voltage level is switched. Here, we report an electrochemical sensor circuit including electrochemical transistors based on poly(3,4-ethyle ... [Appl. Phys. Lett. 93, 203301 (2008)] published Tue Nov 18, 2008.

Mechanical and electrical coupling at metal-insulator-metal nanoscale contacts

Doo-In Kim, Namboodiri Pradeep, Frank W. DelRio, and Robert F. Cook
Mechanical and electrical coupling at nanoscale metallic contacts was investigated using a conducting-probe atomic force microscope (AFM). The current-voltage responses were non-Ohmic, symmetric about zero bias, with conductance values smaller than the quantum conductance limit, which indicate elect ... [Appl. Phys. Lett. 93, 203102 (2008)] published Tue Nov 18, 2008.

Electrical bistable memory device based on a poly(styrene-b-4-vinylpyridine) nanostructured diblock copolymer thin film

Ching-Mao Huang, Yung-Sheng Liu, Chen-Chia Chen, Kung-Hwa Wei, and Jeng-Tzong Sheu
This paper describes the performance of a nonvolatile memory device based on a solution-processed poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) diblock copolymer thin film. The Al/PS-b-P4VP/indium tin oxide memory device featuring metal-coordinated 30 nm P4VP cores exhibited an ON/OFF ratio of 2 x 10, ... [Appl. Phys. Lett. 93, 203303 (2008)] published Tue Nov 18, 2008.

Synthesis and transport property of AgSbTe[sub 2] as a promising thermoelectric compound

Heng Wang, Jing-Feng Li, Minmin Zou, and Tao Sui
Polycrystalline AgSbTe ternary compound materials with high phase purity were fabricated using a combined process of mechanical alloying and spark plasma sintering. It was found that stoichiometric AgSbTe is a promising composition for low-and-mediate temperature applications, whose ZT reaches 1.59 ... [Appl. Phys. Lett. 93, 202106 (2008)] published Tue Nov 18, 2008.

Merged phototransistor pixel with enhanced near infrared response and flicker noise reduction for biomolecular imaging

Gholamreza Chaji, Arokia Nathan, and Quentin Pankhurst
A top-illuminated, nonoffset amorphous silicon (a-Si) photo thin-film transistor structure is presented for biomolecular imaging applications. The device yields a high gate-modulated response to near infrared wavelengths, enhanced by trapped assisted absorption in the transistor. In addition, its fl ... [Appl. Phys. Lett. 93, 203504 (2008)] published Tue Nov 18, 2008.

Advanced luminescence based effective series resistance imaging of silicon solar cells

H. Kampwerth, T. Trupke, J. W. Weber, and Y. Augarten
A technique for fast and spatially resolved measurement of the effective series resistance of silicon solar cells from luminescence images is introduced. Without compromising the speed of existing luminescence based series resistance imaging methods, this method offers significant advantages in that ... [Appl. Phys. Lett. 93, 202102 (2008)] published Tue Nov 18, 2008.

M[o-umlaut]ssbauer studies on structural ordering and magnetic properties of melt-spun Ni--Fe--Ga ribbons

N. V. Rama Rao, R. Gopalan, M. Manivel Raja, V. Chandrasekaran, and K. G. Suresh
Ribbons of ferromagnetic shape memory NiFeGa (x=0 and 0.12) alloys were prepared at wheel speeds of 12 and 35 m/s by melt spinning technique. The structural (site) disorder and the associated changes in the magnetic properties of the ribbons were investigated by Fe Mossbauer spectroscopy and magnet ... [Appl. Phys. Lett. 93, 202503 (2008)] published Tue Nov 18, 2008.

Strain-induced low dimensional confinement structures

Nadir Sekkal and V. R. Velasco
We propose here confinement structures similar to heterostructures and superlattices. The present structures can be obtained by applying strain to a single material in a periodic or aperiodic way. The conversion of an indirect gap into an optical active direct or quasidirect gap problem has also bee ... [Appl. Phys. Lett. 93, 201104 (2008)] published Tue Nov 18, 2008.

A polymer/fullerene based photodetector with extremely low dark current for x-ray medical imaging applications

T. Agostinelli, M. Campoy-Quiles, J. C. Blakesley, R. Speller, D. D. C. Bradley et al.
Organic photodetectors for use in medical x-ray digital imaging applications are fabricated from poly(3-hexylthiophene) and [6,6]-phenyl C-butyric acid methyl ester using a solution-based, temperature assisted deposition protocol. In comparison to bulk heterojunction structures, the proposed protoco ... [Appl. Phys. Lett. 93, 203305 (2008)] published Tue Nov 18, 2008.

An UV photochromic memory effect in proton-based WO[sub 3] electrochromic devices

Yong Zhang, S.-H. Lee, A. Mascarenhas, and S. K. Deb
We report an UV photochromic memory effect on a standard proton-based WO electrochromic device. It exhibits two memory states, associated with the colored and bleached states of the device, respectively. Such an effect can be used to enhance device performance (increasing the dynamic range), re-ener ... [Appl. Phys. Lett. 93, 203508 (2008)] published Tue Nov 18, 2008.

Light-induced hysteresis characteristics of copper phthalocyanine organic thin-film transistors

Lijuan Zhen, Liwei Shang, Ming Liu, Deyu Tu, Zhuoyu Ji et al.
Applying a bidirectional sweeping gate voltage, the white-light illuminated copper phthalocyanine thin-film transistors (CuPc-TFTs) show obvious hysteresis effect and the hysteresis window is 32 V. This effect is dominated by the additional carriers generated by photoirradiation. Although small hyst ... [Appl. Phys. Lett. 93, 203302 (2008)] published Tue Nov 18, 2008.

Separation enhancement in pinched flow fractionation

Asger Laurberg Vig and Anders Kristensen
A method for enhancing the separation in the microfluidic size separation technique called pinched flow fractionation (PFF) is demonstrated experimentally and analyzed by numerical calculations. The enhancement is caused by a geometrical modification of the original PFF design. Seven different polys ... [Appl. Phys. Lett. 93, 203507 (2008)] published Tue Nov 18, 2008.

Low specific contact resistance of heavily phosphorus-doped diamond film

Hiromitsu Kato, Hitoshi Umezawa, Norio Tokuda, Daisuke Takeuchi, Hideyo Okushi et al.
Low resistive contacts were formed on heavily phosphorus-doped diamond (n) films with phosphorus concentration of over ~10 cm grown on (111) diamond substrates by microwave plasma enhanced chemical vapor deposition with precise control of growth conditions. The specific contact resistance was deter ... [Appl. Phys. Lett. 93, 202103 (2008)] published Tue Nov 18, 2008.

Symmetrical frequency response in a split ring resonator based transmission line

A. L. Borja, J. Carbonell, V. E. Boria, and D. Lippens
A coplanar waveguide line based on a split ring resonator technology and loaded with metallic strips and capacitances is proposed. The addition of series capacitances to previous unit cell implementations dramatically improves the upper band rejection levels and provides a transmission response almo ... [Appl. Phys. Lett. 93, 203505 (2008)] published Tue Nov 18, 2008.

Reorientation of (Mn[sub Ti][sup [double-prime]] - V[sub O][sup [bullet][bullet]])[sup x] defect dipoles in acceptor-modified BaTiO[sub 3] single crystals: An electron paramagnetic resonance study

Lixue Zhang, Emre Erdem, Xiaobing Ren, and Rudiger-A. Eichel
The effect of external electric fields on the orientation of (MnV) defect dipoles in ferroelectric BaTiO single crystals and its interplay with the domain structure were investigated by means of electron paramagnetic resonance (EPR) spectroscopy and optical microscopy. The results show that in speci ... [Appl. Phys. Lett. 93, 202901 (2008)] published Tue Nov 18, 2008.

Compact 2 x 2 tapered multimode interference couplers based on SU-8 polymer rectangular waveguides

Liu Yang, Bo Yang, Zhen Sheng, Jianwei Wang, Daoxin Dai et al.
A 2 x 2 tapered multimode interference (MMI) coupler is designed and fabricated by using air-cladded SU-8 rectangular waveguide, which is effective in reducing the device size and improving the self-imaging quality. The parabolically tapered MMI section is used to reduce further the size of the MMI ... [Appl. Phys. Lett. 93, 203304 (2008)] published Tue Nov 18, 2008.

Coherent anti-Stokes Raman microspectroscopy using spectral focusing with glass dispersion

Israel Rocha-Mendoza, Wolfgang Langbein, and Paola Borri
We demonstrate experimentally that coherent anti-Stokes Raman microspectroscopy with high spectral resolution is achieved using femtosecond laser pulses chirped up to a few picoseconds by glass elements of known group-velocity dispersion without significant intensity losses. By simply choosing the l ... [Appl. Phys. Lett. 93, 201103 (2008)] published Tue Nov 18, 2008.