Applied Physics Letters: All Topics

Terahertz vacuum electronic circuits fabricated by UV lithographic molding and deep reactive ion etching

Young-Min Shin, Larry R. Barnett, Diana Gamzina, Neville C. Luhmann, Jr., Mark Field et al.
The 0.22 THz vacuum electronic circuits fabricated by UV lithography molding and deep reactive ion etching processes are under investigation for submillimeter wave applications. Eigenmode transient simulations show that, accounting for realistic values of our currently achievable fabrication toleran ... [Appl. Phys. Lett. 95, 181505 (2009)] published Fri Nov 6, 2009.

Field dependence of barrier heights and luminescence properties in polar and nonpolar InGaN/GaN single quantum wells

Hooyoung Song, Jin Soak Kim, Eun Kyu Kim, Sung-Ho Lee, and Sung-Min Hwang
The external field dependence of barrier heights and the internal field dependence of luminescence properties in InGaN/GaN single quantum wells (SQWs) with polar (x=0.13) and nonpolar (x=0.15) orientations were investigated. The conduction band offset of a SQW was characterized by using deep level t ... [Appl. Phys. Lett. 95, 182109 (2009)] published Fri Nov 6, 2009.

Purified Si film formation from metallurgical-grade Si by hydrogen plasma induced chemical transport

Hiromasa Ohmi, Akihiro Goto, Daiki Kamada, Yoshinori Hamaoka, Hiroaki Kakiuchi et al.
Purified Si film is prepared directly from metallurgical-grade Si (MG-Si) by using hydrogen plasma induced chemical transport at subatmospheric pressure. The purification mechanism is based on the different hydrogenation behaviors of the various impurity elements in MG-Si. The prepared Si films clea ... [Appl. Phys. Lett. 95, 181506 (2009)] published Fri Nov 6, 2009.

Relationship between band alignment and chemical states upon annealing in HfSiON/SiON stacked films on Si substrates

T. Tanimura, S. Toyoda, H. Kamada, H. Kumigashira, M. Oshima et al.
We have investigated the relationship between band alignment and chemical states in HfSiON/SiON stacked films on Si substrates by photoemission spectroscopy and x-ray absorption spectroscopy. Valence-band maxima mainly derived from N 2p states in HfSiON films are closely related to NHf bonding confi ... [Appl. Phys. Lett. 95, 183113 (2009)] published Fri Nov 6, 2009.

Infrared carpet cloak designed with uniform silicon grating structure

Xiaofei Xu, Yijun Feng, Yu Hao, Juming Zhao, and Tian Jiang
Through a particularly chosen coordinate transformation, we propose an optical carpet cloak that only requires homogeneous anisotropic dielectric material. The proposed cloak could be easily imitated and realized by alternative layers of isotropic dielectrics. To demonstrate the cloaking performance ... [Appl. Phys. Lett. 95, 184102 (2009)] published Fri Nov 6, 2009.

Temperature- and magnetic-field-controlled magnetic pole reversal in a molecular magnetic compound

S. M. Yusuf, Amit Kumar, and J. V. Yakhmi
A highly reversible (bipolar) switching of magnetization in a Prussian blue type molecular magnet CuMn[Fe(CN)]zHO using low magnetic fields is demonstrated. The studied molecular compound also shows both positive and negative magnetocaloric effects below its magnetic ordering temperature. A molecula ... [Appl. Phys. Lett. 95, 182506 (2009)] published Fri Nov 6, 2009.

Nonequilibrium dynamical ferromagnetism of interacting single-molecule magnets

Gui-Bin Liu and Bang-Gui Liu
We propose a nonequilibrium Monte Carlo (MC) approach to explore nonequilibrium dynamical ferromagnetism of interacting single molecule magnets (SMMs). Both quantum spin tunneling and thermally activated spin reversal are implemented in the same MC simulation framework. Applied to a typical example, ... [Appl. Phys. Lett. 95, 183110 (2009)] published Fri Nov 6, 2009.

Observation of asymmetrical pinning of domain walls in notched Permalloy nanowires using electron holography

Kai He, David J. Smith, and Martha R. McCartney
Field-driven domain-wall motion and pinning in notched Permalloy nanowires have been observed using electron holography and Lorentz microscopy. Transverse domain walls (TDWs) were identified and different aspects of their behavior, including nucleation, injection, pinning, and depinning, were studie ... [Appl. Phys. Lett. 95, 182507 (2009)] published Fri Nov 6, 2009.

Accelerated interface defect removal in amorphous/crystalline silicon heterostructures using pulsed annealing and microwave heating

T. F. Schulze, H. N. Beushausen, T. Hansmann, L. Korte, and B. Rech
We present postdeposition annealing experiments on undoped amorphous-/n-type crystalline silicon [(i)a-Si:H/(n)c-Si/(i)a-Si:H] heterostructures used as precursors for a-Si:H/c-Si high-efficiency solar cells. Comparing conventional hotplate-heating with pulsed microwave-heating we obtain excellent in ... [Appl. Phys. Lett. 95, 182108 (2009)] published Fri Nov 6, 2009.

Chemical changes on the green emitter tris(8-hydroxy-quinolinato)aluminum during device aging of p-i-n-structured organic light emitting diodes

Sebastian Scholz, Bjorn Lussem, and Karl Leo
Metal organic fluorescent and phosphorescent emitters are widely used in organic light emitting devices (OLEDs). Iridium-based triplet emitters are known to undergo chemical reactions with other materials during OLED aging. The material tris(8-hydroxy-quinolinato)aluminum (Alq), which is widely used ... [Appl. Phys. Lett. 95, 183309 (2009)] published Fri Nov 6, 2009.

Mechanistic investigation of ZnO nanowire growth

Simas Rackauskas, Albert G. Nasibulin, Hua Jiang, Ying Tian, Gintare Statkute et al.
ZnO nanowire (NW) growth mechanism was investigated in a nonvapor and noncatalytic approach for the controlled NW synthesis in a second time scale. The experimental results showed what ZnO NW growth was determined by migration of zinc interstitials and vacancies in a ZnO layer, which should be also ... [Appl. Phys. Lett. 95, 183114 (2009)] published Fri Nov 6, 2009.

Magnetic and conductive dead layer at the LaCaMnOSrTiO:Nb interface

S. Liang, J. R. Sun, J. Wang, and B. G. Shen
Interfacial properties of the LaCaMnO films grown on SrTiO and SrTiO:Nb, respectively, have been experimentally studied. An interface layer, ~13 or ~4.4 nm for the films on SrTiO or SrTiO:Nb, with degenerated magnetic/conductive properties is found in the film. The most remarkable result is the sig ... [Appl. Phys. Lett. 95, 182509 (2009)] published Fri Nov 6, 2009.

Optical properties of 1.3 [mu]m InAs/GaAs bilayer quantum dots with high areal density

C. Y. Ngo, S. F. Yoon, D. R. Lim, Vincent Wong, and S. J. Chua
InAs/GaAs bilayer quantum dots (BQDs) are interesting structures for long wavelength emission due to its ability to tune the areal density and dot size separately. However, the need for two sets of growth rate and temperature for the respective QD layers complicates the growth procedures. Furthermor ... [Appl. Phys. Lett. 95, 181913 (2009)] published Fri Nov 6, 2009.

Influence of molecular weight on the solar cell performance of double-crystalline donor-acceptor block copolymers

Michael Sommer, Sven Huttner, Ullrich Steiner, and Mukundan Thelakkat
We investigate the influence of the molecular weight of double-crystalline donor-acceptor block copolymers comprised of poly(3-hexylthiophene) as donor and poly(perylene bisimide acrylate) as acceptor segments on the device performance of polymer solar cells. Two block copolymers 1 and 2 exhibiting ... [Appl. Phys. Lett. 95, 183308 (2009)] published Fri Nov 6, 2009.

Investigation of the electrocaloric effect in a PbMgNbO-PbTiO relaxor thin film

T. M. Correia, J. S. Young, R. W. Whatmore, J. F. Scott, N. D. Mathur et al.
Permittivity measurements of a 0.93PMN-0.07PT thin film show a broad maximum near 35 degrees C, and an anomaly at the depolarizing temperature T=18 degrees C on heating only, suggesting a dipolar glass-relaxor phase transition. No structural phase transition at 18 degrees C is apparent from ferro ... [Appl. Phys. Lett. 95, 182904 (2009)] published Fri Nov 6, 2009.

Effect of polarization on spectral switches in the diffraction of stochastic electromagnetic beams

Liuzhan Pan, Zhiguo Zhao, Chaoliang Ding, and Baida Lu
We consider the stochastic electromagnetic Gaussian Schell-model (EGSM) beam and show that the polarization of stochastic electromagnetic EGSM beams in the source plane affect spectral switches of diffracted stochastic electromagnetic EGSM beams in the far field. For two cases of fully coherent and ... [Appl. Phys. Lett. 95, 181112 (2009)] published Fri Nov 6, 2009.

Aging of AlGaN quantum well light emitting diode studied by scanning near-field optical spectroscopy

A. Pinos, S. MarcinkeviCius, J. Yang, Y. Bilenko, M. Shatalov et al.
Emission from a 285 nm AlGaN quantum well light emitting diode has been studied by scanning near-field optical spectroscopy. The scans revealed micrometer-size domainlike areas emitting with a higher intensity and at a longer wavelength; presumably, because of a lower AlN molar fraction in these reg ... [Appl. Phys. Lett. 95, 181914 (2009)] published Fri Nov 6, 2009.

Birefringence-induced mode-dependent tuning of liquid crystal infiltrated InGaAsP photonic crystal nanocavities

M. A. Dundar, H. H. J. E. Kicken, A. Yu. Silov, R. Notzel, F. Karouta et al.
Mode-dependent shifts of resonant frequencies of cavities in liquid crystal (LC) infiltrated planar photonic crystals (PhC) are experimentally observed when the temperature is varied across the LC ordering transition. The shifts can be in opposite directions, even for two very similar nearly degener ... [Appl. Phys. Lett. 95, 181111 (2009)] published Fri Nov 6, 2009.

X-ray magnetic circular dichroism studies of Fe doped fullerene and highly oriented pyrolytic graphite

Amit Kumar, P. Thakur, N. B. Brookes, and D. K. Avasthi
We report the x-ray magnetic circular dichroism (XMCD) studies on Fe doped fullerene thin film and bulk highly oriented pyrolytic graphite. The element-specific hysteresis curves were recorded by measuring the XMCD at the Fe L edge as a function of the applied field strength at different temperature ... [Appl. Phys. Lett. 95, 182511 (2009)] published Fri Nov 6, 2009.

Soluble state high resolution atomic force microscopy study of Alzheimer's beta-amyloid oligomers

Gajendra S. Shekhawat, Mary P. Lambert, Saurabh Sharma, Pauline T. Velasco, Kirsten L. Viola et al.
We report here the direct observation of high resolution structures of assemblies of Alzheimer beta-amyloid oligomers and monomers using liquid atomic force microscopy (AFM). Visualization of nanoscale features of Abeta oligomers (also known as ADDLs) was carried out in tapping mode AFM in F12 solut ... [Appl. Phys. Lett. 95, 183701 (2009)] published Fri Nov 6, 2009.

High temperature stable monodisperse superparamagnetic core-shell iron-oxide@SnO nanoparticles

Xiaobin Xu, Mingyuan Ge, Cen Wang, and J. Z. Jiang
Monodisperse superparamagnetic SnO-coated iron-oxide nanoparticles (~16.4 nm) have been synthesized via thermal decomposition. The thickness of SnO shells can be controlled from 15 nm. As-prepared SnO-coated iron-oxide nanoparticles with high saturation magnetization (18 A m/kg), are stable up to ... [Appl. Phys. Lett. 95, 183112 (2009)] published Fri Nov 6, 2009.

Effect of pressure on electrospray characteristics

Ioan Marginean, Jason S. Page, Ryan T. Kelly, Keqi Tang, and Richard D. Smith
An experimental study of pulsating electrosprays operated at subambient pressure is reported. The pressure domain that affords stable electrospray operation appears to be limited by the vapor pressure of the liquid. The voltage driving the electrospray is shown to have a logarithmic dependence on pr ... [Appl. Phys. Lett. 95, 184103 (2009)] published Fri Nov 6, 2009.

All-optical detection of phase fronts of propagating spin waves in a NiFe microstripe

K. Vogt, H. Schultheiss, S. J. Hermsdoerfer, P. Pirro, A. A. Serga et al.
We present the determination of the wavelength and phase of propagating spin waves in magnetic microstructures made of NiFe using the shorted end of a coplanar waveguide for local excitation. The spin wave characteristics have been measured by phase resolved Brillouin light scattering microscopy. Th ... [Appl. Phys. Lett. 95, 182508 (2009)] published Fri Nov 6, 2009.

Effects of surface ligands on the charge memory characteristics of CdSe/ZnS nanocrystals in TiO thin film

Seung-Hee Kang, Ch. Kiran Kumar, Zonghoon Lee, Velimir Radmilovic, and Eui-Tae Kim
Charge memory characteristics have been systematically studied based on colloidal CdSe/ZnS nanocrystal quantum dots (QDs) embedded in ~50 nm-thick TiO film. Ligand-capped QDs showed negligible electron charging effect, implying that the electron affinity of QDs was significantly decreased by surfac ... [Appl. Phys. Lett. 95, 183111 (2009)] published Fri Nov 6, 2009.

Microbubble-enhanced ultrasound-modulated fluorescence in a turbid medium

Baohong Yuan, Yuan Liu, Patrick M. Mehl, and Joseph Vignola
The feasibility of using ultrasound to modulate fluorescence in a turbid medium is still in debate due to the difficulty of detecting the modulated signal. We have demonstrated a system that could detect the weak signals of ultrasound-modulated fluorescence (UMF) by using a broadband lock-in amplifi ... [Appl. Phys. Lett. 95, 181113 (2009)] published Fri Nov 6, 2009.

Frequency upconverted lasing of nanocrystal quantum dots in microbeads

Chunfeng Zhang, Fan Zhang, An Cheng, Brian Kimball, Andrew Y. Wang et al.
Stable, frequency upconverted lasing of semiconductor nanocrystal quantum dots was demonstrated in silica microbeads under two-photon pumping conditions. Upon infrared excitation, the stimulated emission of the nanocrystal-doped microbeads exhibits sharp peaks at lambda~610 nm with narrow line widt ... [Appl. Phys. Lett. 95, 183109 (2009)] published Fri Nov 6, 2009.

Observation of the zero-magnetic-field exciton spin splitting in high quality bulk GaAs and AlGaAs

E. V. Kozhemyakina, K. S. Zhuravlev, A. Amo, D. Ballarini, and L. Vina
We present an experimental study of the zero-magnetic-field exciton spin splitting measured by time-resolved photoluminescence in high purity bulk GaAs and AlGaAs samples. The dynamics of the splitting differs from that observed in two dimensions. Initially, the splitting increases during 100250 ps ... [Appl. Phys. Lett. 95, 182107 (2009)] published Fri Nov 6, 2009.

Spin-dependent intergranular transport in highly spin-polarized CoFeS thin films

M. Manno, R. Frakie, B. Bolon, and C. Leighton
Magnetic and magnetotransport measurements on polycrystalline thin film CoFeS, a system that exhibits tunable conduction electron spin polarization in bulk, are reported. The films exhibit a low field hysteretic magnetoresistance (MR) due to spin-dependent intergranular tunneling, thus providing a s ... [Appl. Phys. Lett. 95, 182510 (2009)] published Fri Nov 6, 2009.

Polarization entanglement with graded-index lenses

Giuseppe Vallone, Gaia Donati, Francesco De Martini, and Paolo Mataloni
By using an optical device based on the integration of a graded-index (GRIN) rod lens and a single-mode optical fiber we efficiently collected photon pairs generated by spontaneous parametric down-conversion. We show that this system preserves the polarization entanglement of the two-photon states. ... [Appl. Phys. Lett. 95, 181110 (2009)] published Fri Nov 6, 2009.

Enhancement of electric force by ion-neutral collisions

G. Makrinich and A. Fruchtman
The measured force exerted on an ion flow by an electric field is found to be larger than the electric force that can be exerted if the ions are collisionless. In addition, the increase of the gas pressure is found to result in an increase of the electric force despite a simultaneous decrease of the ... [Appl. Phys. Lett. 95, 181504 (2009)] published Thu Nov 5, 2009.

Mechanics of hemispherical electronics

Shuodao Wang, Jianliang Xiao, Inhwa Jung, Jizhou Song, Heung Cho Ko et al.
A simple analytical model is established for the development of hemisphere electronics, which has many important applications in electronic-eye cameras and related curvilinear systems. The photodetector arrays, made in planar mesh layouts with conventional techniques, are deformed and transferred on ... [Appl. Phys. Lett. 95, 181912 (2009)] published Thu Nov 5, 2009.

Enhanced thermal stability of Pt electrodes for flat epitaxial biferroic-YMnO/Pt heterostructures

R. Bachelet, R. Muralidharan, F. Rigato, N. Dix, X. Marti et al.
We have investigated the thermal stability of platinum electrodes on oxide substrates for oxide-based devices. We show that flat epitaxial Pt(111) bottom electrodes, deposited on SrTiO(111) and AlO(0001) substrates, can be stable against dewetting up to usual oxide-deposition temperatures (T) by inc ... [Appl. Phys. Lett. 95, 181907 (2009)] published Thu Nov 5, 2009.

Highly efficient cross-linked PbS nanocrystal/C hybrid heterojunction photovoltaic cells

S. W. Tsang, H. Fu, R. Wang, J. Lu, K. Yu et al.
We present a highly efficient hybrid heterojunction photovoltaic (PV) cell with a colloidal inorganic nanocrystal (NC) electron donor and an organic electron acceptor. The heterojunction is formed by a thin film of cross-linked PbS NCs and a vacuum deposited C layer. Compared to the PbS-only PV cell ... [Appl. Phys. Lett. 95, 183505 (2009)] published Thu Nov 5, 2009.

Design of graphene electronic devices using nanoribbons of different widths

G. G. Naumis, M. Terrones, H. Terrones, and L. M. Gaggero-Sager
We present a simple design of a field effect transistor based on graphene nanoribbons, taking advantage of the metallic and semiconductor nature of nanoribbons with different widths. Such device could be constructed by using lithography techniques. The conductance of the proposed device is obtained ... [Appl. Phys. Lett. 95, 182104 (2009)] published Thu Nov 5, 2009.

Determination and enhancement of the capacitance contributions in carbon nanotube based electrode systems

M. Hoefer and P. R. Bandaru
We characterize the methodology of, and a possible way to enhance, the capacitance of carbon nanotube (CNT) electrode based electrochemical capacitors. Argon irradiation was used to controllably incorporate extrinsic defects into CNTs and increase the magnitude of both the pseudocapacitance and doub ... [Appl. Phys. Lett. 95, 183108 (2009)] published Thu Nov 5, 2009.

Investigation of electron wave function hybridization in GaInAs/InP arrays

T. P. Martin, M. S. Fairbanks, B. C. Scannell, C. A. Marlow, H. Linke et al.
We present a measurement technique for quantifying coupling between semiconductor quantum dots in an array. This technique employs magnetoconductance fluctuations to probe the decrease in the average spacing of the quantum energy levels as the electron wave functions in the dots undergo hybridizatio ... [Appl. Phys. Lett. 95, 182105 (2009)] published Thu Nov 5, 2009.

Measurement of heat capacity and enthalpy of formation of nickel silicide using nanocalorimetry

Ravi K. Kummamuru, Lito De La Rama, Liang Hu, Mark D. Vaudin, Mikhail Y. Efremov et al.
The total enthalpy of reaction and heat capacity to 850 degrees C were measured using differential scanning nanocalorimetry (nano-DSC) for the reaction of a nickel and silicon bilayer at heating rates up to 10 K/s. Exothermic dips in heat capacity attributed to nickel silicide formation were found ... [Appl. Phys. Lett. 95, 181911 (2009)] published Thu Nov 5, 2009.

Energy band-alignment of a multimetal-layer gated metal-oxide-semiconductor structure

Zilan Li, Michel Houssa, Tom Schram, Stefan De Gendt, and Kristin De Meryer
The energy band-alignment of a multimetal-layer gated metal-oxide-semiconductor structure is investigated. An analytical expression for the Fermi level of the metal stack is derived. It is shown that the thin metal layer contacting the gate dielectric plays a critical role in determining the work fu ... [Appl. Phys. Lett. 95, 183506 (2009)] published Thu Nov 5, 2009.

Low-temperature magnetotransport behaviors of heavily Mn-doped (Ga,Mn)As films with high ferromagnetic transition temperature

L. Chen, S. Yan, P. F. Xu, J. Lu, W. Z. Wang et al.
We report the low-temperature magnetotransport behaviors of (Ga,Mn)As films with the nominal Mn concentration x larger than 10%. The ferromagnetic transition temperature T can be enhanced to 191 K after postgrowth annealing (Ga,Mn)As with x=20%. The temperature T, corresponding to the resistivity mi ... [Appl. Phys. Lett. 95, 182505 (2009)] published Thu Nov 5, 2009.

Thermal properties of char obtained by pyrolysis: A molecular dynamics simulation study

Maxim A. Makeev and Deepak Srivastava
The thermal conductivity of pyrolytic char obtained by ultrahigh temperature decomposition of polyethylene specimen via molecular dynamics simulations is investigated as a function of temperature and microstructural characteristics. We find that the simulated thermal conductivity dependence on the a ... [Appl. Phys. Lett. 95, 181908 (2009)] published Thu Nov 5, 2009.

Individual charge-trapping dislocations in an ionic insulator

Zhongchang Wang, Susumu Tsukimoto, Mitsuhiro Saito, and Yuichi Ikuhara
Insulating oxide materials find widespread technological applications where how their inside dislocations behave are known to influence or control performance. Here we demonstrate, by first-principles calculations on MgO, that individual dislocations can trap charges within empty space around their ... [Appl. Phys. Lett. 95, 184101 (2009)] published Thu Nov 5, 2009.

Coupling between even- and oddlike modes in a single asymmetric photonic crystal waveguide

Xiaoyu Mao, Yidong Huang, Wei Zhang, and Jiangde Peng
The photonic crystal (PC) is an important structure for realizing optical integrative circuits. Nowadays, most PC based passive devices operate by utilizing the coupling either between several PC waveguides or between PC waveguides and resonance cavities. In this letter, we present a coupling mechan ... [Appl. Phys. Lett. 95, 183106 (2009)] published Thu Nov 5, 2009.

Engineering single photon emitters by ion implantation in diamond

B. Naydenov, R. Kolesov, A. Batalov, J. Meijer, S. Pezzagna et al.
Diamond provides unique technological platform for quantum technologies including quantum computing and communication. Controlled fabrication of optically active defects is a key element for such quantum toolkit. Here we report the production of single color centers emitting in the blue spectral reg ... [Appl. Phys. Lett. 95, 181109 (2009)] published Thu Nov 5, 2009.

Direct integration of active Ge(SiSn) semiconductors on Si(100)

Junqi Xie, J. Tolle, V. R. D'Costa, A. V. G. Chizmeshya, J. Menendez et al.
Doped and intrinsic GeSiSn alloys are synthesized directly on Si(100) using simple deposition chemistries and their optical and electrical properties are determined. Tuning the Si/Sn ratio at ~4 yields strain-free films with Ge-like cell dimensions, while variation of the ratio around this value pro ... [Appl. Phys. Lett. 95, 181909 (2009)] published Thu Nov 5, 2009.

Ultrafast imaging of photoelectron packets generated from graphite surface

Ramani K. Raman, Zhensheng Tao, Tzong-Ru Han, and Chong-Yu Ruan
We present an electron projection imaging method to study the ultrafast evolution of photoelectron density distribution and transient fields near the surface. The dynamical profile of the photoelectrons from graphite reveals an origin of a thermionic emission, followed by an adiabatic process leadin ... [Appl. Phys. Lett. 95, 181108 (2009)] published Thu Nov 5, 2009.

All graphene electromechanical switch fabricated by chemical vapor deposition

Kaveh M. Milaninia, Marc A. Baldo, Alfonso Reina, and Jing Kong
We demonstrate an electromechanical switch comprising two polycrystalline graphene films; each deposited using ambient pressure chemical vapor deposition. The top film is pulled into electrical contact with the bottom film by application of approximately 5 V between the layers. Contact is broken by ... [Appl. Phys. Lett. 95, 183105 (2009)] published Thu Nov 5, 2009.

Stable and reversible optoelectrical dual-mode data storage based on a ferrocenlylspiropyran molecule

Ying Ma, Chengshan Niu, Yongqiang Wen, Guo Li, Jingxia Wang et al.
A spiropyran molecule bonded with ferrocene (SPFc) was synthesized as data storage medium. Optical recording pattern was obtained through the reversible modulation of UV and visible light on the SPFc film, which exhibited good reversibility compared with the spiropyran without ferrocene moiety. In a ... [Appl. Phys. Lett. 95, 183307 (2009)] published Thu Nov 5, 2009.

Large electromechanical coupling factor film bulk acoustic resonator with X-cut LiNbO layer transfer

M. Pijolat, S. Loubriat, S. Queste, D. Mercier, A. Reinhardt et al.
As layer transfer techniques have been notably improved in the past years, lithium niobate (LiNbO) appears as a candidate for the next generation of ultrawide band radio frequency (rf) filters. Depending on the crystalline orientation, LiNbO can achieve electromechanical coupling factors Kt more tha ... [Appl. Phys. Lett. 95, 182106 (2009)] published Thu Nov 5, 2009.

Studies of charge transfer processes across donor-acceptor interface using a field effect transistor geometry

Manohar Rao and K. S. Narayan
The existence of donor-type polymer field effect transistors (FETs), which are FETs exhibiting p-type characteristics and acceptor-type molecular FETs with n-type characteristics, provide an interesting possibility of a combined active bilayer system, especially under photoexcitation. We present a d ... [Appl. Phys. Lett. 95, 183306 (2009)] published Thu Nov 5, 2009.

Hot and super-hot hydrogen atoms in microwave plasma

E. Tatarova, E. Felizardo, F. M. Dias, M. Lino da Silva, C. M. Ferreira et al.
Super-hot (kinetic energy ~48 eV) and hot (kinetic energy ~0.3 eV) H atoms were detected in a surface wave (500 MHz) generated H plasma column, at pressure p=0.01 mbar, from the analysis of the H, H, H, and H emission line profiles. These profiles were found to evolve from single Gaussian to bi-G ... [Appl. Phys. Lett. 95, 181503 (2009)] published Thu Nov 5, 2009.

Thermalization of exciton states in silicon nanocrystals

Brian Julsgaard, Ying-Wei Lu, Peter Balling, and Arne Nylandsted Larsen
Silicon nanocrystals are studied by time-resolved fluorescence spectroscopy. After laser excitation the bright and dark exciton ground state levels are populated at random, but subsequently the decay curves reveal a thermalization between these levels. The characteristic thermalization time is found ... [Appl. Phys. Lett. 95, 183107 (2009)] published Thu Nov 5, 2009.

Quantum confined Stark effect and corresponding lifetime reduction in a single InGaN quantum disk

Mark J. Holmes, Young S. Park, Jamie H. Warner, and Robert A. Taylor
Time-integrated and time-resolved microphotoluminescence studies were carried out on InGaN quantum disks embedded in GaN nanocolumns grown by molecular beam epitaxy. Emission at ~3.33 eV from confined states was detected and observed to blueshift with excitation power; a result of charge screening ... [Appl. Phys. Lett. 95, 181910 (2009)] published Thu Nov 5, 2009.

Study on dielectric and magnetodielectric properties of LuFeO ceramics

Xiaobo Wu, Xiaofei Wang, Yunfei Liu, Wei Cai, Song Peng et al.
Polycrystalline LuFeO ceramics with garnet structure were prepared by a solid-state reaction method. A dielectric relaxor behavior at low temperature was observed which may come from the dipolar effects associated with the charge carrier hopping between Fe and Fe. It is noticeable that their magneto ... [Appl. Phys. Lett. 95, 182903 (2009)] published Thu Nov 5, 2009.

Bistable twisted-bend and twisted-nematic liquid crystal display

Y. W. Li and H. S. Kwok
Bistability of twisted-bend and twisted configuration is found. It is based on the elastic and topological inequivalency of director orientation. Multiple states of minimum local energy exist, with appropriate boundary conditions. The effects of elastic constants, d/P ratio and pretilt angle are als ... [Appl. Phys. Lett. 95, 181107 (2009)] published Thu Nov 5, 2009.

Controlling the spectrum of x-rays generated in a laser-plasma accelerator by tailoring the laser wavefront

S. P. D. Mangles, G. Genoud, S. Kneip, M. Burza, K. Cassou et al.
By tailoring the wavefront of the laser pulse used in a laser-wakefield accelerator, we show that the properties of the x-rays produced due to the electron beam's betatron oscillations in the plasma can be controlled. By creating a wavefront with coma, we find that the critical energy of the synchro ... [Appl. Phys. Lett. 95, 181106 (2009)] published Wed Nov 4, 2009.

Bifurcation topology tuning of a mixed behavior in nonlinear micromechanical resonators

N. Kacem and S. Hentz
We report the experimental observation of a four-bifurcation-point (or five possible amplitudes for a given frequency) behavior of electrostatically actuated micromechanical resonators, called the mixed (first hardening then softening) behavior. We also demonstrate both analytically and experimental ... [Appl. Phys. Lett. 95, 183104 (2009)] published Wed Nov 4, 2009.

Self-assembled nanodielectrics and silicon nanomembranes for low voltage, flexible transistors, and logic gates on plastic substrates

Hoon-Sik Kim, Sang Min Won, Young-Geun Ha, Jong-Hyun Ahn, Antonio Facchetti et al.
This letter reports the fabrication and electrical characterization of mechanically flexible and low operating voltage transistors and logic gates (NOT, NAND, and NOR gates) using printed silicon nanomembranes and self-assembled nanodielectrics on thin plastic substrates. The transistors exhibit eff ... [Appl. Phys. Lett. 95, 183504 (2009)] published Wed Nov 4, 2009.

Flexible metamaterials for wireless strain sensing

Rohat Melik, Emre Unal, Nihan Kosku Perkgoz, Christian Puttlitz, and Hilmi Volkan Demir
We proposed and demonstrated flexible metamaterial-based wireless strain sensors that include arrays of split ring resonators (SRRs) to telemetrically measure strain. For these metamaterial sensors, we showed that a flexible substrate (e.g., Kapton tape) delivers greater sensitivity and a more linea ... [Appl. Phys. Lett. 95, 181105 (2009)] published Wed Nov 4, 2009.

First-principles study on the enhancement of lithium storage capacity in boron doped graphene

Xianlong Wang, Zhi Zeng, Hyojun Ahn, and Guoxiu Wang
The adsorption of Li ions on boron doped graphene was investigated using a first-principles method. Our results show that, as boron doping turns graphene into an electron-deficient system, more Li ions can be captured around boron doped centers than in pristine graphene. One boron atom doped into gr ... [Appl. Phys. Lett. 95, 183103 (2009)] published Wed Nov 4, 2009.

Optical position clamping with predictive control

Heikki Ojala, Anders Korsback, Anders E. Wallin, and Edward Haeggstrom
We increase the effective stiffness of optical tweezers by position clamping a polystyrene bead with a predictive feedback control algorithm. This algorithm mitigates the effect of feedback loop delay. Hence, higher gain than with proportional control can be employed, which results in higher effecti ... [Appl. Phys. Lett. 95, 181104 (2009)] published Wed Nov 4, 2009.

Improved red-response in thin film a-Si:H solar cells with soft-imprinted plasmonic back reflectors

Vivian E. Ferry, Marc A. Verschuuren, Hongbo B. T. Li, Ruud E. I. Schropp, Harry A. Atwater et al.
The impact of controlled nanopatterning on the Ag back contact of an n-i-p a-Si:H solar cell was investigated experimentally and through electromagnetic simulation. Compared to a similar reference cell with a flat back contact, we demonstrate an efficiency increase from 4.5% to 6.2%, with a 26% incr ... [Appl. Phys. Lett. 95, 183503 (2009)] published Tue Nov 3, 2009.

Composition-dependent dielectric properties of RbTiOPO single crystals

Jna. Gavalda, J. J. Carvajal, X. Mateos, M. Aguilo, and F. Diaz
We measured the ionic conductivity for two single crystals of RbTiOPO grown in self-fluxes with different chemical composition. Ionic conductivity depended on the composition of the self-flux solution in which the crystal was grown. One of the samples showed an anisotropic behavior along the three c ... [Appl. Phys. Lett. 95, 182902 (2009)] published Tue Nov 3, 2009.

Time domain analyses of the converse magnetoelectric effect in a multiferroic metallic glass-relaxor ferroelectric heterostructure

Yajie Chen, Anton L. Geiler, Trifon Fitchorov, Carmine Vittoria, and V. G. Harris
The dynamic time domain response of the converse magnetoelectric effect in a multiferroic Metglas/Pb(MgNb)OPbTiO (PMN-PT) heterostructure, under the application of a square waveform electric field excitation of 8 kV/cm at a frequency of 0.4 Hz, is reported. The relaxation behavior followed a stretch ... [Appl. Phys. Lett. 95, 182501 (2009)] published Tue Nov 3, 2009.

Coengineering of ferroelectric and exchange bias properties in BiFeO based heterostructures

J. Allibe, I. C. Infante, S. Fusil, K. Bouzehouane, E. Jacquet et al.
The magnetoelectric coupling existing in some multiferroics may allow the low-power electrical control of spintronics devices. However, room temperature magnetoelectric multiferroics are extremely rare, an exception being BiFeO, a ferroelectric antiferromagnet. To be used for electrically controllab ... [Appl. Phys. Lett. 95, 182503 (2009)] published Tue Nov 3, 2009.

Oxidation of silver electrodes induces transition from conventional to inverted photovoltaic characteristics in polymer solar cells

Jong Bok Kim, Chang Su Kim, Youn Sang Kim, and Yueh-Lin Loo
Oxidation of silver top electrodes in polymer solar cells induces the devices to exhibit a transition from conventional to inverted photovoltaic characteristics. As silver oxidizes, its work function increases from 4.3 to 5.0 eV. The silver top electrode thus reverts from collecting electrons to col ... [Appl. Phys. Lett. 95, 183301 (2009)] published Tue Nov 3, 2009.

Direct observation of individual Barkhausen avalanches in nucleation-mediated magnetization reversal processes

Mi-Young Im, Peter Fischer, Dong-Hyun Kim, and Sung-Chul Shin
We report the scaling behavior of Barkhausen avalanches [H. Barkhausen, Z. Phys. 20, 401 (1919).] along the hysteresis loop of a CoCrPt alloy film with perpendicular magnetic anisotropy for every field step of 200 Oe. Individual Barkhausen avalanches are directly observed via soft x-ray microscopy w ... [Appl. Phys. Lett. 95, 182504 (2009)] published Tue Nov 3, 2009.

Mechanism for tautomerization induced conductance switching of naphthalocyanin molecule

Qiang Fu, Jinlong Yang, and Yi Luo
Reaction mechanism for tautomerization process of a single naphthalocyanin molecule has been studied using density functional theory. It is found that tautomerization of the naphthalocyanin molecule is not a concerted reaction, but a step-wise process in that one hydrogen atom transfers after anothe ... [Appl. Phys. Lett. 95, 182103 (2009)] published Tue Nov 3, 2009.

Minority electron unipolar photodetectors based on type II InAs/GaSb/AlSb superlattices for very long wavelength infrared detection

B.-M. Nguyen, S. Bogdanov, S. Abdollahi Pour, and M. Razeghi
We present a hybrid photodetector design that inherits the advantages of traditional photoconductive and photovoltaic devices. The structure consists of a barrier layer blocking the transport of majority holes in a p-type semiconductor, resulting in an electrical transport due to minority carriers w ... [Appl. Phys. Lett. 95, 183502 (2009)] published Tue Nov 3, 2009.

Low voltage operation in picene thin film field-effect transistor and its physical characteristics

Yumiko Kaji, Naoko Kawasaki, Xuesong Lee, Hideki Okamoto, Yasuyuki Sugawara et al.
Low voltage operation of picene thin film field-effect transistor (FET) has been realized with 40 nm thick SiO gate dielectrics coated by two polymers, Cytop and polystyrene. The picene FETs operated in low absolute gate voltage |V| below 15 V for Cytop coated SiO and 30 V for polystyrene coated SiO ... [Appl. Phys. Lett. 95, 183302 (2009)] published Tue Nov 3, 2009.

Optical confirmation of biaxial nematic (N) phase in a bent-core mesogen

Yun Jang, Vitaly P. Panov, Antoni Kocot, J. K. Vij, A. Lehmann et al.
A bent-core mesogen with different end groups has been studied for different surface conditions in both planar and homeotropic cells using techniques for measuring biaxiality and optical switching. Biaxial nematic phase observed in between the uniaxial nematic and smectic phases is evidenced by a sh ... [Appl. Phys. Lett. 95, 183304 (2009)] published Tue Nov 3, 2009.

Low-density band-gap states in pentacene thin films probed with ultrahigh-sensitivity ultraviolet photoelectron spectroscopy

Tomoki Sueyoshi, Hirohiko Fukagawa, Masaki Ono, Satoshi Kera, and Nobuo Ueno
We detected a very low density of electronic states in the band gap of a nondoped pentacene thin film by using ultraviolet photoelectron spectroscopy with ultrahigh sensitivity and ultralow background. The gap states, which may originate from the highest occupied molecular orbital (HOMO) state in im ... [Appl. Phys. Lett. 95, 183303 (2009)] published Tue Nov 3, 2009.

Giant tunneling magnetoresistance up to 330% at room temperature in sputter deposited CoFeAl/MgO/CoFe magnetic tunnel junctions

Wenhong Wang, Hiroaki Sukegawa, Rong Shan, Seiji Mitani, and Koichiro Inomata
Magnetoresistance ratio up to 330% at room temperature (700% at 10 K) has been obtained in a spin-valve-type magnetic tunnel junction (MTJ) consisting of a full-Heusler alloy CoFeAl electrode and a MgO tunnel barrier fabricated on a single crystal MgO (001) substrate by sputtering method. The output ... [Appl. Phys. Lett. 95, 182502 (2009)] published Tue Nov 3, 2009.

Shaping site-controlled uniform arrays of SiGe/Si(001) islands by in situ annealing

J. J. Zhang, A. Rastelli, H. Groiss, J. Tersoff, F. Schaffler et al.
We investigate the effect of in situ annealing on the shape, size, and chemical composition of ordered SiGe islands grown on pit-patterned Si(001) substrates. In contrast to planar substrates, intermixing with substrate material occurs symmetrically during annealing because the substrate patterning ... [Appl. Phys. Lett. 95, 183102 (2009)] published Tue Nov 3, 2009.

Singlet energy transfer and singlet-singlet annihilation in light-emitting blends of organic semiconductors

A. Ruseckas, J. C. Ribierre, P. E. Shaw, S. V. Staton, P. L. Burn et al.
Excitation energy transfer from host to guest is studied in spin-cast blends of 4,4-bis(N-carbazolyl)biphenyl (CBP) and a phosphorescent fac-tris(2-phenylpyridyl)iridium(III)-cored dendrimer using time resolved fluorescence. The kinetics of energy transfer are consistent with homogeneous dispersion ... [Appl. Phys. Lett. 95, 183305 (2009)] published Tue Nov 3, 2009.

Spiral nucleation of silicon solidified on heterogeneous surface of carbon nanocones

H. Li, Y. F. Li, K. M. Liew, J. X. Zhang, and X. F. Liu
Molecular dynamics studies are carried out to examine the spiral nucleation mode of silicon solidified on the surface of carbon nanocones (CNCs). The silicon atoms are concentrated to form magic multilayered nanocones composed of coaxial and equidistant conical shells. Heterogeneous nucleation that ... [Appl. Phys. Lett. 95, 183101 (2009)] published Tue Nov 3, 2009.

Spontaneous buildup of surface potential with a thin film of a zwitterionic molecule giving noncentrosymmetric crystal structure

Jun'ya Tsutsumi, Hiroyuki Yoshida, Richard Murdey, and Naoki Sato
Surface potentials were examined using the Kelvin method for thin films of zwitterionic molecules, pyridinium 1,3-dihydro-1,3-dioxo-2H-inden-2-ylide (PI or IPB) and two nitrogen-substituted derivatives. Spontaneous buildup of the surface potential on the film (5.5 V at a film thickness of 300 nm) wa ... [Appl. Phys. Lett. 95, 182901 (2009)] published Tue Nov 3, 2009.

Trigonal paramagnetic interface defect in epitaxial GeN/(111)Ge

A. P. D. Nguyen, A. Stesmans, V. V. Afanas'ev, R. R. Lieten, and G. Borgs
We report on the observation by electron spin resonance (ESR) of an anisotropic paramagnetic defect at the interface of epitaxially grown GeN/(111)Ge entities with nanometer thin GeN layers. The defect exhibits trigonal C symmetry characterized by g[approximate]2.0023 and g[approximate]2.0032, and i ... [Appl. Phys. Lett. 95, 183501 (2009)] published Tue Nov 3, 2009.

Evolution of laser-induced carbon particle breakdown in gas

Hong-Yu Chu and Man-Chon Si
We investigate the evolution of the laser-induced breakdown of a suspended micrometer-sized carbon particle at 460 torr N gas environment. An elliptical hot gas resulting from the ionizations of the particle breakdown and the gas breakdown is observed. We show that the deformation of the elliptical ... [Appl. Phys. Lett. 95, 181502 (2009)] published Tue Nov 3, 2009.

Enhancement of magnetoelectric effect in multiferroic fibrous nanocomposites via size-dependent material properties

E. Pan, X. Wang, and R. Wang
We investigate the effective material properties of a multiferroic fibrous nanocomposite with size effects along its interface. The closed-form expression of the effective moduli of the nanocomposite shows that its response with interface effects depends on the size of the embedded fibers in the com ... [Appl. Phys. Lett. 95, 181904 (2009)] published Mon Nov 2, 2009.

Near-field imaging of femtosecond laser ablated sub-lambda/4 holes in lithium niobate

Airan Rodenas, Jorge Lamela, Daniel Jaque, Gines Lifante, Francisco Jaque et al.
We report on the direct femtosecond laser ablation of sub-lambda/4 (80250 nm) holes in LiNbO crystals and on its local near-field imaging. We show that the near-field transmission of holes can feature an attenuation of ~75% at hole central position, and a ~20% transmission enhancement at its sides. ... [Appl. Phys. Lett. 95, 181103 (2009)] published Mon Nov 2, 2009.

Broadband planar Luneburg lens based on complementary metamaterials

Qiang Cheng, Hui Feng Ma, and Tie Jun Cui
A two-dimensional broadband low-loss Luneburg lens has been designed based on the complementary metamaterials. The complementary I-shaped unit has been chosen as the basic cell due to its high resonant frequency, whose effective constitutive parameters are nearly constants at low frequencies. Numeri ... [Appl. Phys. Lett. 95, 181901 (2009)] published Mon Nov 2, 2009.

Measurement of effective electron mass in biaxial tensile strained silicon on insulator

S. F. Feste, Th. Schapers, D. Buca, Q. T. Zhao, J. Knoch et al.
We present measurements of the effective electron mass in biaxial tensile strained silicon on insulator (SSOI) material with 1.2 GPa stress and in unstrained SOI. Hall-bar metal oxide semiconductor field effect transistors on 60 nm SSOI and SOI were fabricated and Shubnikovde Haas oscillations in th ... [Appl. Phys. Lett. 95, 182101 (2009)] published Mon Nov 2, 2009.

Kinetics of a transient silicide during the reaction of Ni thin film with (100)Si

Dominique Mangelinck, Khalid Hoummada, and Ivan Blum
In situ measurements of the kinetics of the transient theta-NiSi phase formation have been obtained by x-ray diffraction and differential scanning calorimetry. A possible mechanism for the transient phase is proposed. It allows to simulate the growth and the consumption of the theta-NiSi during the ... [Appl. Phys. Lett. 95, 181902 (2009)] published Mon Nov 2, 2009.

Thermal-induced refractive-index planar waveguide laser

Hongxiang Kang (康宏向), Haitao Zhang (张海涛), and Dongsheng Wang (王东生)
The feasibility of a thermal-induced refractive-index planar waveguide laser was demonstrated. The condition for the guided modes to be confined in the gain region was calculated. A thermal-induced refractive-index planar waveguide laser was made simply by pumping a thin center layer of a slab cryst ... [Appl. Phys. Lett. 95, 181102 (2009)] published Mon Nov 2, 2009.

Negative differential resistance in conductive polymer and semiconducting quantum dot nanocomposite systems

S. Biswas, M. Dutta, and M. A. Stroscio
We report the room temperature negative differential resistance (NDR) phenomenon in nanocomposite heterostructures made of semiconducting quantum dots embedded in conductive polymers. The peak to valley ratio of the current is 91 at room temperature which increases to 2965 at 77 K. The current volta ... [Appl. Phys. Lett. 95, 182102 (2009)] published Mon Nov 2, 2009.

A simple atmospheric pressure room-temperature air plasma needle device for biomedical applications

X. Lu, Z. Xiong, F. Zhao, Y. Xian, Q. Xiong et al.
Rather than using noble gas, room air is used as the working gas for an atmospheric pressure room-temperature plasma. The plasma is driven by submicrosecond pulsed directed current voltages. Several current spikes appear periodically for each voltage pulse. The first current spike has a peak value o ... [Appl. Phys. Lett. 95, 181501 (2009)] published Mon Nov 2, 2009.

Pressure enhancement of the isostructural cubic decomposition in TiAlN

B. Alling, M. Oden, L. Hultman, and I. A. Abrikosov
The influence of pressure on the phase stabilities of TiAlN solid solutions has been studied using first principles calculations. We find that the application of hydrostatic pressure enhances the tendency for isostructural decomposition, including spinodal decomposition. The effect originates in the ... [Appl. Phys. Lett. 95, 181906 (2009)] published Mon Nov 2, 2009.

Anomaly of critical stress in stress-induced transformation of NiCoMnIn metamagnetic shape memory alloy

Xiao Xu, Wataru Ito, Rie Y. Umetsu, Ryosuke Kainuma, and Kiyohito Ishida
Stress-induced martensitic transformation below room temperature for a NiCoMnIn single-crystal, in which no martensitic transformation occurs during cooling down to 4.2 K under zero stress, was investigated by using compression test. The equilibrium stress estimated from the critical stresses in str ... [Appl. Phys. Lett. 95, 181905 (2009)] published Mon Nov 2, 2009.

Carrier relaxation dynamics of ZnCdSe/C core/shell nanocrystals with phase separation as studied by time-resolved cathodoluminescence

Y. Estrin, D. H. Rich, O. Moshe, Sayan Bhattacharyya, and A. Gedanken
The optical properties and carrier relaxation kinetics of ZnCdSe/C core/shell nanocrystals with compositional phase separation occurring on a ~15 nm size scale were examined with time-resolved cathodoluminescence (CL) spectroscopy and imaging. The CL spectral lineshape was found to depend on the le ... [Appl. Phys. Lett. 95, 181903 (2009)] published Mon Nov 2, 2009.

Electrically tunable terahertz quantum-cascade laser with a heterogeneous active region

Suraj P. Khanna, Mohammed Salih, Paul Dean, A. Giles Davies, and Edmund H. Linfield
We demonstrate experimentally a terahertz frequency quantum-cascade laser which can be tuned electronically, in a step-wise manner from typically 3.07 to 3.40 THz, by changing the applied electric field across the device. To achieve this, the gallium growth rate was successively reduced during growt ... [Appl. Phys. Lett. 95, 181101 (2009)] published Mon Nov 2, 2009.

Conoscopic observation of director reorientation during Poiseuille flow of a nematic liquid crystal

C. J. Holmes, S. L. Cornford, and J. R. Sambles
Director reorientation under pressure driven (Poiseuille) flow is observed conoscopically for the liquid crystal 5CB aligned at an azimuthal angle of 45 degrees to the direction of flow. A polyimide surface treatment (AL 1254) is used to promote planar homogeneous alignment and rubbed to produce an ... [Appl. Phys. Lett. 95, 171114 (2009)] published Fri Oct 30, 2009.

Reversible ferromagnetic spin ordering governed by hydrogen in Co-doped ZnO semiconductor

Yong Chan Cho, Sung-Jin Kim, Seunghun Lee, Su Jae Kim, Chae Ryong Cho et al.
We report a reversible manipulation of short-range spin ordering in Co-doped ZnO through hydrogenation and dehydrogenation processes. In both magnetic-circular dichroism and superconducting quantum interference device measurements, the ferromagnetism was clearly induced and removed by the injection ... [Appl. Phys. Lett. 95, 172514 (2009)] published Fri Oct 30, 2009.

Mg-based metallic glass/titanium interpenetrating phase composite with high mechanical performance

Y. Sun, H. F. Zhang, A. M. Wang, H. M. Fu, Z. Q. Hu et al.
We report an Mg-based metallic glass/titanium interpenetrating phase composite in which constituent phases form a homogeneously interconnected network. The porous titanium constrains shear bands propagation thoroughly and promotes shear bands branching and intersection subsequently. The homogeneous ... [Appl. Phys. Lett. 95, 171910 (2009)] published Fri Oct 30, 2009.

Publisher's Note: Active control of surface plasmon polaritons by optical isomerization of an azobenzene polymer film [Appl. Phys. Lett. 95, 101102 (2009)]

D. G. Zhang, X.-C. Yuan, A. Bouhelier, G. H. Yuan, P. Wang et al.
Abstract not available. [Appl. Phys. Lett. 95, 179903 (2009)] published Fri Oct 30, 2009.

Magnetization reversal process of ferromagnetic granular thin films probed by magnetization-induced second harmonic generation

Y. F. Chiang, Y. J. Hsu, T. M. Liu, H. W. Chu, J. G. Lin et al.
We propose to use magnetization-induced second harmonic generation (MSHG) technique to explore the magnetization reversal process of cobalt granular thin films. The three-dimensional magnetization reversal process can be visualized by analyzing the polarization dependent MSHG hysteresis curves. It i ... [Appl. Phys. Lett. 95, 172515 (2009)] published Fri Oct 30, 2009.

Influence of cytoskeleton on nanoparticle migration in biological cells

A. Tarasenko and L. Jastrabik
Magnetic nanoparticles have shown great promise for their use in many biomedical applications. Here we develop a quantifiable cell model to investigate particle diffusion. The tracer, jump, and chemical diffusion coefficients have been calculated for different densities of cytoskeleton proteins. ... [Appl. Phys. Lett. 95, 173705 (2009)] published Fri Oct 30, 2009.

Determining surface Fermi level pinning position of InN nanowires using electrolyte gating

D. R. Khanal, W. Walukiewicz, J. Grandal, E. Calleja, and J. Wu
We demonstrate quantitative determination of surface Fermi level pinning position in InN nanowires using polymer electrolyte gating and three-dimensional (3D) electrostatic modeling of charge distribution. We find pinning of the Fermi level 0.60.7 eV above the conduction band minimum at the surface ... [Appl. Phys. Lett. 95, 173114 (2009)] published Fri Oct 30, 2009.

Spin-torque driven ferromagnetic resonance in a nonlinear regime

W. Chen, G. de Loubens, J.-M. L. Beaujour, J. Z. Sun, and A. D. Kent
Spin-valve based nanojunctions incorporating Co|Ni multilayers with perpendicular anisotropy were used to study spin-torque driven ferromagnetic resonance (ST-FMR) in a nonlinear regime. Perpendicular field swept resonance lines were measured under a large amplitude microwave current excitation, whi ... [Appl. Phys. Lett. 95, 172513 (2009)] published Fri Oct 30, 2009.

Thermochromic polymer opals

Jason Sussman, David Snoswell, Andreas Kontogeorgos, Jeremy J. Baumberg, and Peter Spahn
Large-scale shear-ordered photonic crystals are shown to exhibit unusual thermochromic properties. By balancing the refractive index of the polymer core and composite shell components at room temperature, transparent films are created, which become colored on heating to 150 degrees C. Since this sc ... [Appl. Phys. Lett. 95, 173116 (2009)] published Fri Oct 30, 2009.

Photocurrent enhancement in polymer:fullerene bulk heterojunction solar cells doped with a phosphorescent molecule

Barry P. Rand, Claudio Girotto, Alexander Mityashin, Afshin Hadipour, Jan Genoe et al.
We demonstrate photocurrent enhancement of up to 20% in polymer:fullerene bulk heterojunction photovoltaic cells via the incorporation of a phosphorescent dopant, without degradation in the open-circuit voltage or fill factor of the device. The enhancement is shown to originate from multiple sources ... [Appl. Phys. Lett. 95, 173304 (2009)] published Fri Oct 30, 2009.

An ultrasmall wavelength-selective channel drop switch using a nanomechanical photonic crystal nanocavity

Yoshiaki Kanamori, Kazunori Takahashi, and Kazuhiro Hane
We propose a nanomechanical channel drop switch by controlling the submicron distance between a nanocavity and photonic crystal (PC) waveguide with an ultrasmall electrostatic comb actuator. Light propagating in the PC waveguide is coupled with a nanocavity and emitted as a drop signal under a reson ... [Appl. Phys. Lett. 95, 171911 (2009)] published Fri Oct 30, 2009.

In vacuo measurement of the sensitivity limit of planar Bragg grating sensors for monolayer detection

Richard M. Parker, James C. Gates, Martin C. Grossel, and Peter G. R. Smith
An exposed Bragg grating incorporated into a planar waveguide was used to form an optical device that acts as a refractive index sensor. The exposed evanescent field causes the Bragg peak to be sensitive to the refractive index of its surroundings. The corresponding shift in peak wavelength can be u ... [Appl. Phys. Lett. 95, 173306 (2009)] published Fri Oct 30, 2009.

Plasmonic waveguide as an efficient transducer for high-density data storage

D. O'Connor, M. McCurry, B. Lafferty, and A. V. Zayats
A design of high optical throughput nanoscale light sources has been proposed based on plasmonic wedge waveguides. It provides localization of the 1500 nm wavelength light at the output of less than 30 x 30 nm area at about 80% coupling efficiency from a dielectric loaded surface plasmon polariton ... [Appl. Phys. Lett. 95, 171112 (2009)] published Fri Oct 30, 2009.

A pathway to p-type wide-band-gap semiconductors

Anderson Janotti, Eric Snow, and Chris G. Van de Walle
Based on first-principles calculations we devise an alternative approach to p-type doping in AlN, ZnO, and ZnMgO. Instead of searching for acceptors on the left of the host atoms in the Periodic Table, we propose to search on the far right. We find that F placed at interstitial sites in AlN, ZnO, an ... [Appl. Phys. Lett. 95, 172109 (2009)] published Fri Oct 30, 2009.

Cavity-enhanced photocurrent generation by 1.55 [mu]m wavelengths linear absorption in a p-i-n diode embedded silicon microring resonator

Hui Chen, Xianshu Luo, and Andrew W. Poon
We demonstrate 20-fold cavity-enhanced photocurrent generation in 1.55 [mu]m wavelengths in a p-i-n diode embedded silicon microring resonator with Q factor of 8000. The on-resonance wavelength shows linear responsivity of 0.12 mA/W upon 0 V bias and 0.25 mA/W upon 15 V bias. We attribute the linea ... [Appl. Phys. Lett. 95, 171111 (2009)] published Fri Oct 30, 2009.

Exciton switching and Peierls transitions in hybrid inorganic-organic self-assembled quantum wells

K. Pradeesh, J. J. Baumberg, and G. Vijaya Prakash
The switching behavior of exciton absorption and photoluminescence is systematically explored in hybrid inorganic-organic multiple quantum well structures, based on (CHNH)PbI thin films and single crystals. Two structural phases found between 15 and 75 degrees C, based on orthorhombic and monoclini ... [Appl. Phys. Lett. 95, 173305 (2009)] published Fri Oct 30, 2009.

The surface activation layer of GaAs negative electron affinity photocathode activated by Cs, Li, and NF

Y. Sun, R. E. Kirby, T. Maruyama, G. A. Mulhollan, J. C. Bierman et al.
The lifetime of GaAs photocathodes can be greatly improved by introducing Li in the Cs+NF activation process. The surface activation layer of such photocathodes is studied by synchrotron radiation photoemission and is compared with GaAs photocathodes activated without Li. The charge distributions of ... [Appl. Phys. Lett. 95, 174109 (2009)] published Fri Oct 30, 2009.

Growth of high-density vertically aligned arrays of carbon nanotubes by plasma-assisted catalyst pretreatment

S. Esconjauregui, B. C. Bayer, M. Fouquet, C. T. Wirth, C. Ducati et al.
A plasma-assisted thermal pretreatment of catalyst films (Ni, Co, or Fe) greatly facilitates the direct growth of high-density vertically aligned arrays of small diameter carbon nanotubes (CNTs) on conductive TiN by purely thermal chemical vapor deposition. Purely thermal catalyst pretreatment gives ... [Appl. Phys. Lett. 95, 173115 (2009)] published Fri Oct 30, 2009.

Correlation of O (1s) and Fe (2p) near edge x-ray absorption fine structure spectra and electrical conductivity of LaSrFeNiO

Selma Erat, Artur Braun, Alejandro Ovalle, Cinthia Piamonteze, Zhi Liu et al.
A-site substitution of La by Sr in polaron conducting ABO-type perovskite LaSrFeNiO causes oxidation of Fe toward Fe and formation of conducting electron holes, as evidenced by Fe (2p) and O (1s) near edge x-ray absorption fine structure spectra. Hole doping is reflected by linear variation of the p ... [Appl. Phys. Lett. 95, 174108 (2009)] published Fri Oct 30, 2009.

Terahertz microfluidic sensor based on a parallel-plate waveguide resonant cavity

Rajind Mendis, Victoria Astley, Jingbo Liu, and Daniel M. Mittleman
We describe a terahertz optical resonator that is ideally suited for highly sensitive and noninvasive refractive-index monitoring. The resonator is formed by machining a rectangular groove into one plate of a parallel-plate waveguide, and is excited using the lowest-order transverse-electric (TE) wa ... [Appl. Phys. Lett. 95, 171113 (2009)] published Fri Oct 30, 2009.

Thermal crosslinking of organic semiconducting polythiophene improves transverse hole conductivity

Ioana R. Gearba, Chang-Yong Nam, Ron Pindak, and C. T. Black
Thermal crosslinking using a suitable radical initiator simultaneously improves electrical conductivity in the semiconducting polymer poly(3-hexylthiophene) and makes the material insoluble. Crosslinked polythiophene shows as much as a fivefold increase in hole conductivity across the film thickness ... [Appl. Phys. Lett. 95, 173307 (2009)] published Fri Oct 30, 2009.

Interlayer magnetostatic coupling induced Co layer coercivity enhancement and exchange bias in [Pd/Co]/Cu/Co spin valves

P. Y. Yang, X. Y. Zhu, F. Zeng, and F. Pan
Interlayer stray field coupling in hybrid perpendicular/Cu/in-plane magnetic anisotropy [Pd/Co]/Cu/Co single spin valves and [Pd/Co]/Cu/Co/Cu/[Co/Pd] dual spin valves was investigated. Enhancements of Co layer coercivity were observed after ac or dc demagnetization of the samples. This effect origin ... [Appl. Phys. Lett. 95, 172512 (2009)] published Fri Oct 30, 2009.

All-optical phase modulations in a silicon wire waveguide at ultralow light levels

Nobuyuki Matsuda (松田信幸), Ryosuke Shimizu (清水亮介), Yasuyoshi Mitsumori (三森康義), Hideo Kosaka (小坂英男), Aya Sato (佐藤綾耶) et al.
Cross-phase modulation (XPM) in a silicon wire waveguide at 1.55 [mu]m telecom band was studied down to ultralow light levels. In the low-power regime, we found that free-carrier dispersion as well as the optical Kerr effect contributes to the XPM. Possible mechanisms of the low-power XPM are discu ... [Appl. Phys. Lett. 95, 171110 (2009)] published Fri Oct 30, 2009.

Shape memory and superelasticity in polycrystalline CuAlNi microwires

Ying Chen, Xuexi Zhang, David C. Dunand, and Christopher A. Schuh
We report a strategy to significantly improve the ductility and achieve large superelastic and shape memory strains in polycrystalline CuAlNi shape memory alloys that are normally brittle. We use a liquid-phase (Taylor) wire forming process to obtain microwires of 10150 [mu]m diameter with a bamboo ... [Appl. Phys. Lett. 95, 171906 (2009)] published Thu Oct 29, 2009.

Controlled generation of resonant electron-electron scattering induced current in quantum well structures

M. Coquelin, G. Strasser, E. Gornik, P. Bakshi, and M. Ciftan
Current voltage measurements on samples designed for the resonant excitation of intersubband plasmons are reported. These resonances which represent collective electron-electron scattering processes contribute a significant amount to the total current under controlled bias conditions. Measurements w ... [Appl. Phys. Lett. 95, 172108 (2009)] published Thu Oct 29, 2009.

Short range ordering in FeGe and FeGa single crystals

Mianliang Huang and Thomas A. Lograsso
We report on the nature of short range ordering (SRO) in slow cooled (100) and (111) FeGa and FeGe single crystals determined by x-ray theta-2theta scans. The SRO of the Ga atoms has at least some D0 character. In contrast Ge atoms only exhibit B2 chemical ordering symmetries in the short range orde ... [Appl. Phys. Lett. 95, 171907 (2009)] published Thu Oct 29, 2009.

Improved model for the angular dependence of excimer laser ablation rates in polymer materials

J. E. A. Pedder, A. S. Holmes, and P. E. Dyer
Measurements of the angle-dependent ablation rates of polymers that have applications in microdevice fabrication are reported. A simple model based on Beer's law, including plume absorption, is shown to give good agreement with the experimental findings for polycarbonate and SU8, ablated using the 1 ... [Appl. Phys. Lett. 95, 174105 (2009)] published Thu Oct 29, 2009.

Erratum: High domain wall velocities induced by current in ultrathin Pt/Co/AlOx wires with perpendicular magnetic anisotropy [Appl. Phys. Lett. 93, 262504 (2008)]

T. A. Moore, I. M. Miron, G. Gaudin, G. Serret, S. Auffret et al.
Abstract not available. [Appl. Phys. Lett. 95, 179902 (2009)] published Thu Oct 29, 2009.

Increases in effective head field gradients in exchange spring media

Jehyun Lee, Dieter Suess, Thomas Schrefl, Julian Dean, and Josef Fidler
Finite head field gradients in combination with switching field distribution of individual grains lead to transition jitter in granular recording media. We studied the effective head field gradients in various recording media structures using finite element micromagnetics. Inhomogeneous reversal was ... [Appl. Phys. Lett. 95, 172509 (2009)] published Thu Oct 29, 2009.

Cerium oxide-chitosan based nanobiocomposite for food borne mycotoxin detection

Ajeet Kaushik, Pratima R. Solanki, M. K. Pandey, Sharif Ahmad, and Bansi D. Malhotra
Cerium oxide nanoparticles (NanoCeO) and chitosan (CH) based nanobiocomposite film deposited onto indium-tin-oxide coated glass substrate has been used to coimmobilize rabbit immunoglobin (r-IgGs) and bovine serum albumin (BSA) for food borne mycotoxin [ochratoxin-A (OTA)] detection. Electrochemical ... [Appl. Phys. Lett. 95, 173703 (2009)] published Thu Oct 29, 2009.

Generalized form of anhysteretic magnetization function for JilesAtherton theory of hysteresis

A. Raghunathan, Y. Melikhov, J. E. Snyder, and D. C. Jiles
A generalized form of anhysteretic magnetization function to extend JilesAtherton theory to different forms of anisotropy has been derived. The general equation for the function has been compared with those of calculations made on the basis of known equations for specific cases: axially anisotropic ... [Appl. Phys. Lett. 95, 172510 (2009)] published Thu Oct 29, 2009.

Direct contact mechanism of Ohmic metallization to AlGaN/GaN heterostructures via Ohmic area recess etching

Liang Wang, Dong-Hyun Kim, and Ilesanmi Adesida
The effects of recess etching of the Ohmic contact area on the performance of Ti/Al/Mo/Au metallization and its interfacial reactions with AlGaN/AlN/GaN epilayers were investigated. The best Ohmic contact performances of 0.31, 0.41, and 0.26 Omega mm for three epilayers from two different sources w ... [Appl. Phys. Lett. 95, 172107 (2009)] published Thu Oct 29, 2009.

Comment on Comparison of air breakdown and substrate injection as mechanisms to induce dielectric charging in microelectromechanical switches [Appl. Phys. Lett. 92, 043502 (2008)]

Zbigniew Olszewski, Conor O'Mahony, Ruth Houlihan, and Russell Duane
The purpose of this comment is to provide additional insight into the reliability of microelectromechanical capacitive switches (MEMSs) investigated by Molinero and Castaner [Appl. Phys. Lett. 92, 043502 (2008)]. We show that the presence or absence of ambient humidity determines whether the shift i ... [Appl. Phys. Lett. 95, 176101 (2009)] published Thu Oct 29, 2009.

Resistance of diamond (100) to hyperthermal atomic oxygen attack

Z. Shpilman, I. Gouzman, E. Grossman, L. Shen, T. K. Minton et al.
The morphology of polycrystalline chemical vapor deposited (CVD) diamond films following the interaction with hyperthermal (~5 eV) atomic oxygen (AO) was studied by atomic force microscopy. Selective etching of the (111) diamond facets occurred, while the (100) facets showed high endurance. The obs ... [Appl. Phys. Lett. 95, 174106 (2009)] published Thu Oct 29, 2009.

Tuning of photonic crystal cavities by controlled removal of locally infiltrated water

Francesca Intonti, Silvia Vignolini, Francesco Riboli, Margherita Zani, Diederik S. Wiersma et al.
We present a spectral tuning mechanism of photonic crystal microcavities based on microfluidics. The microinfiltration with water of one or few cavity holes and its subsequent controlled evaporation allow us to tune the cavity resonances in a spectral range larger than 20 nm, with subnanometer accur ... [Appl. Phys. Lett. 95, 173112 (2009)] published Thu Oct 29, 2009.

Mg doping and its effect on the semipolar GaN(11[overline 2]2) growth kinetics

L. Lahourcade, J. Pernot, A. Wirthmuller, M. P. Chauvat, P. Ruterana et al.
We report the effect of Mg doping on the growth kinetics of semipolar GaN(11[overline 2]2) synthesized by plasma-assisted molecular-beam epitaxy. Mg tends to segregate on the surface, inhibiting the formation of the self-regulated Ga film which is used as a surfactant for the growth of undoped and S ... [Appl. Phys. Lett. 95, 171908 (2009)] published Thu Oct 29, 2009.

Real time observation of partial dislocations in thin colloidal crystals

Yi-Yong Luo, Shu-Xin Hu, Ying Lu, Zhen-Hong Mai, and Ming Li
We use laser diffraction microscopy to visualize in real time the motion of partial dislocations in thin colloidal crystals confined in flat capillaries. The results show that the formation of partial dislocation loops with their associated stacking faults is an energetically preferred strain-relaxa ... [Appl. Phys. Lett. 95, 174107 (2009)] published Thu Oct 29, 2009.

Leakage current and reverse-bias luminescence in InGaN-based light-emitting diodes

M. Meneghini, N. Trivellin, M. Pavesi, M. Manfredi, U. Zehnder et al.
This paper reports an electro-optical analysis of the correlation between reverse-bias leakage current and luminescence in light-emitting diodes based on InGaN. The results of the analysis suggest that (i) the main mechanism responsible for leakage current conduction is tunneling, (ii) leakage curre ... [Appl. Phys. Lett. 95, 173507 (2009)] published Thu Oct 29, 2009.

Pulsed-laser printing of organic thin-film transistors

Ludovic Rapp, Abdou Karim Diallo, Anne Patricia Alloncle, Christine Videlot-Ackermann, Frederic Fages et al.
Organic thin-film transistors have been fabricated using laser-induced forward transfer as spatially resolved laser-printing method. Using this technique, source and drain electrodes were deposited from silver nanoparticle ink and the copper phthalocyanine (CuPc) was used to form the active layer. B ... [Appl. Phys. Lett. 95, 171109 (2009)] published Thu Oct 29, 2009.

Mg doping of thermochromic VO films enhances the optical transmittance and decreases the metal-insulator transition temperature

N. R. Mlyuka, G. A. Niklasson, and C. G. Granqvist
Thermochromic films of MgVO were made by reactive dc magnetron sputtering onto heated glass. The metal-insulator transition temperature decreased by ~3 K/at. %Mg, while the optical transmittance increased concomitantly. Specifically, the transmittance of visible light and of solar radiation was enh ... [Appl. Phys. Lett. 95, 171909 (2009)] published Thu Oct 29, 2009.

A scattering model for surface-textured thin films

Klaus Jager and Miro Zeman
We present a mathematical model that relates the surface morphology of randomly surface-textured thin films with the intensity distribution of scattered light. The model is based on the first order Born approximation [see e.g., M. Born and E. Wolf, Principles of Optics, 7th ed. (Cambridge University ... [Appl. Phys. Lett. 95, 171108 (2009)] published Thu Oct 29, 2009.

Electronegativity equalization model for interface barrier formation at reactive metal/organic contacts

J. X. Tang, Y. Q. Li, S. D. Wang, C. S. Lee, and S. T. Lee
A general model based on electronegativity equalization method (EEM) is proposed for a quantitative formulation of barrier formation at reactive metal/organic interfaces. The present model predicts for molecular bonding formation a linear dependence of barrier heights on the degree of partial charge ... [Appl. Phys. Lett. 95, 173303 (2009)] published Thu Oct 29, 2009.

Erratum: Electroconductance in single-wall carbon nanotubes [Appl. Phys. Lett. 95, 032111 (2009)]

Manu Jaiswal, C. S. Suchand Sangeeth, and Reghu Menon
Abstract not available. [Appl. Phys. Lett. 95, 179901 (2009)] published Thu Oct 29, 2009.

Microwave energy absorption driven by dynamic structural and magnetization states in FeB metallic glass ribbons

R. Nicula, K. Ishizaki, M. Stir, J.-M. Catala-Civera, and S. Vaucher
The kinetics of the microwave crystallization of FeB metallic glasses was investigated in situ using the time-resolved x-ray diffraction method. It is shown that the recorded thermal profile during the microwave exposure of the ribbons bears a close relationship with the dynamic magnetization state ... [Appl. Phys. Lett. 95, 174104 (2009)] published Thu Oct 29, 2009.

Microwave absorption in YBaCuO-manganite superlattices

P. Gierlowski, K. Werner-Malento, P. Przyslupski, and C. J. van der Beek
We report on results of direct microwave absorption measurements of ReBMnO/YBaCuO half metal/d-wave superconductor superlattices (where ReLa and Pr) and (BSr and Ca) for microwave frequencies in the range from 9 to 20 GHz. The measurements of the entire heterostructure were performed mostly at tempe ... [Appl. Phys. Lett. 95, 172511 (2009)] published Thu Oct 29, 2009.

Inactivation of HN viruses exposed to acidic ozone water

Han S. Uhm, Kwang H. Lee, and Baik L. Seong
The inactivation of HN viruses upon exposure to acidic ozone water was investigated using chicken allantoic fluids of different dilutions, pH values, and initial ozone concentrations. The inactivation effect of the acidic ozone water was found to be stronger than the inactivation effect of the ozone ... [Appl. Phys. Lett. 95, 173704 (2009)] published Thu Oct 29, 2009.

An oxide thermal rectifier

W. Kobayashi, Y. Teraoka, and I. Terasaki
We have experimentally demonstrated thermal rectification as bulk effect. According to a theoretical design of a thermal rectifier, we have prepared an oxide thermal rectifier made of two cobalt oxides with different thermal conductivities, and have made an experimental system to detect the thermal ... [Appl. Phys. Lett. 95, 171905 (2009)] published Thu Oct 29, 2009.

Impact of Sn/Zn ratio on the gate bias and temperature-induced instability of Zn-In-Sn-O thin film transistors

Min Ki Ryu, Shinhyuk Yang, Sang-Hee Ko Park, Chi-Sun Hwang, and Jae Kyeong Jeong
We investigated the effect of the Sn/Zn ratio in the amorphous Zn-In-Sn-O (ZITO) system on the gate voltage stress-induced stability of the resulting thin film transistors (TFTs). The device stability of the TFTs with a composition channel of Zn:In:Sn=0.35:0.20:0.45 (device C) was dramatically impro ... [Appl. Phys. Lett. 95, 173508 (2009)] published Thu Oct 29, 2009.

In situ probing of electromechanical properties of an individual ZnO nanobelt

Anjana Asthana, Kasra Momeni, Abhishek Prasad, Yoke Khin Yap, and Reza Shahbazian Yassar
We report here, an investigation on electrical and structural-microstructural properties of an individual ZnO nanobelt via in situ transmission electron microscopy using an atomic force microscopy (AFM) system. The I-V characteristics of the ZnO nanobelt, just in contact with the AFM tip indicates t ... [Appl. Phys. Lett. 95, 172106 (2009)] published Thu Oct 29, 2009.

Nematic anchoring on carbon nanotubes

Rajratan Basu and Germano S. Iannacchione
A dilute suspension of carbon nanotubes (CNTs) in a nematic liquid crystal (LC) does not disturb the LC director. Due to a strong LC-CNT anchoring energy and structural symmetry matching, CNT long axis follows the director field, possessing enhanced dielectric anisotropy of the LC media. This strong ... [Appl. Phys. Lett. 95, 173113 (2009)] published Thu Oct 29, 2009.

Soliton source generation in a few-mode tellurite microstructure fiber

Xin Yan, Guanshi Qin, Meisong Liao, Takenobu Suzuki, Atsushi Mori et al.
We report broad near-infrared soliton and associated dispersive wave source generation (12281867 nm) and tunable green third harmonic generation (528542 nm) by LP mode excitation in a few-mode tellurite microstructure fiber pumped by a 1557 nm femtosecond fiber laser. The fiber presents a wide ran ... [Appl. Phys. Lett. 95, 171107 (2009)] published Thu Oct 29, 2009.

Fabrication and characterization of InGaN p-i-n homojunction solar cell

Xiao-mei Cai, Sheng-wei Zeng, and Bao-ping Zhang
InGaN p-i-n homojunction solar cells with different In content are studied. The measured open circuit voltages (V) are 2.24, 1.34, and 0.96 V, for x=0.02, 0.12, and 0.15, respectively. By comparing the x-ray rocking curves, the I-V characteristics and the external quantum efficiencies, it's demonstr ... [Appl. Phys. Lett. 95, 173504 (2009)] published Wed Oct 28, 2009.

Ab initio-derived correlations for defect-dopant interactions in electronic materials

Mohit Haran and Paulette Clancy
This letter describes a parameter-free, simulation-free route to predict dopant-defect energetics under given hydrostatic strained silicon lattices using readily available physical constants such as electronegativity and size, and dimensionless correlations derived from density functional theory cal ... [Appl. Phys. Lett. 95, 172104 (2009)] published Wed Oct 28, 2009.

Influence of GeSi interfacial layer on GeGe optical phonon mode in SiO films embedded with Ge nanocrystals

L. Z. Liu, F. Gao, X. L. Wu, T. H. Li, and Paul K. Chu
The GeGe optical phonon peak at 300 cm acquired from amorphous SiO films embedded with Ge nanocrystals by Raman scattering is sensitive to the Si content. When the Si concentration is high, a thin GeSi interfacial layer forms around the Ge nanocrystals. A tensile stress is produced to partially off ... [Appl. Phys. Lett. 95, 171105 (2009)] published Wed Oct 28, 2009.

Magnetostructural coupling and magnetocaloric effect in NiMnIn

B. Li, W. J. Ren, Q. Zhang, X. K. Lv, X. G. Liu et al.
Magnetic-field-induced martensitic phase transition and the concomitant change of volume are investigated in NiMnIn alloy. A well-defined linear relationship is found between the quantity characterizing magnetic degree of freedom and the thermal expansion on behalf of structural degree of freedom, w ... [Appl. Phys. Lett. 95, 172506 (2009)] published Wed Oct 28, 2009.

Experimental observation of subluminal and superluminal light propagation in rhodamine 6G-doped polymethyl methacrylate

Wending Zhang, Feng Gao, Guoquan Zhang, Wei Li, Xinzheng Zhang et al.
Nondegenerate two-wave coupling process and group velocity change in the paraxial part of an intensity-modulated and focused transverse electromagnetic beam (TEM beam in the article) was observed in the rhodamine 6G(R6G)-doped polymethyl methacrylate (PMMA) but not in the pure PMMA. The typical supe ... [Appl. Phys. Lett. 95, 171106 (2009)] published Wed Oct 28, 2009.

Virtual circular array using material-embedded linear source distributions

Do-Hoon Kwon
Linear arrays of sources embedded inside a thin material slab are designed such that they radiate the same fields as a circular array of radiators in free space in a two-dimensional configuration. The design is based on the coordinate transformation approach, where a circular domain containing a dis ... [Appl. Phys. Lett. 95, 173503 (2009)] published Wed Oct 28, 2009.

Room temperature ferromagnetism in nanostructured ZnOAl system

S. J. Chen, K. Suzuki, and J. S. Garitaonandia
The origin of the room-temperature ferromagnetism (RTF) in ZnO-based dilute magnetic semiconductors remains controversial. We experimentally demonstrate here that it is possible to induce RTF in ball milled (ZnO)/Al without any ferromagnetic dopant. Our work shows that RTF in (ZnO)/Al (x=00.5) can b ... [Appl. Phys. Lett. 95, 172507 (2009)] published Wed Oct 28, 2009.

Fabrication of large addition energy quantum dots in graphene

J. Moser and A. Bachtold
We present a simple technique to fabricate graphene quantum dots in a cryostat. It relies upon the controlled rupture of a suspended graphene sheet subjected to the application of a large electron current. This results in the in situ formation of a clean and ultranarrow constriction, which hosts one ... [Appl. Phys. Lett. 95, 173506 (2009)] published Wed Oct 28, 2009.

Microphotoluminescence study of exciton polaritons guided in ZnO nanorods

Wenliang Li, Min Gao, Xiaoxian Zhang, Dongfang Liu, Lian-Mao Peng et al.
By confocal microphotoluminescence spectroscopy, we study the influence of the localized excitation position on the guided near band edge emission from the end facets of ZnO nanorods. An increased propagation distance of the guided emission causes dramatically depressed excitonic emission and pronou ... [Appl. Phys. Lett. 95, 173109 (2009)] published Wed Oct 28, 2009.

1 mm ultrafast superconducting stripline molecule detector

N. Zen (全伸幸), A. Casaburi, S. Shiki (志岐成友), K. Suzuki (鈴木宏治), M. Ejrnaes et al.
Superconducting stripline detectors (SSLDs) are promising for detecting keV molecules at nanosecond response times and with mass-independent detection efficiency. However, a fast response time is incompatible with practical centimeter detector size. A parallel configuration of striplines provides a ... [Appl. Phys. Lett. 95, 172508 (2009)] published Wed Oct 28, 2009.

Reversible hysteresis for broadband magnetopiezoelastic energy harvesting

Samuel C. Stanton, Clark C. McGehee, and Brian P. Mann
We model and experimentally validate a nonlinear energy harvester capable of bidirectional hysteresis. In particular, both hardening and softening response within the quadratic potential field of a power generating piezoelectric beam (with a permanent magnet end mass) is invoked by tuning nonlinear ... [Appl. Phys. Lett. 95, 174103 (2009)] published Wed Oct 28, 2009.

Magnetic remanent states and quasistatic switching behavior of Fe split-rings for spin field-effect-transistor applications

J. H. Lee, S. N. Holmes, B. Hong, P. E. Roy, M. D. Mascaro et al.
The magnetic remanent states and switching behavior of Fe thin-film split-rings are investigated using magnetic force microscopy, magnetoresistance measurements, and micromagnetic simulations in order to assess their suitability as spin-filter contacts for spin field-effect-transistors. The gaps bet ... [Appl. Phys. Lett. 95, 172505 (2009)] published Wed Oct 28, 2009.

Demonstration of high performance long wavelength infrared type II InAs/GaSb superlattice photodiode grown on GaAs substrate

S. Abdollahi Pour, B-M. Nguyen, S. Bogdanov, E. K. Huang, and M. Razeghi
We report the growth and characterization of long wavelength infrared type-II InAs/GaSb superlattice photodiodes with a 50% cut-off wavelength at 11 [mu]m, on GaAs substrate. Despite a 7.3% lattice mismatch to the substrate, photodiodes passivated with polyimide exhibit an RA value of 35 Omega cm ... [Appl. Phys. Lett. 95, 173505 (2009)] published Wed Oct 28, 2009.

Dynamics of self-assembled droplet etching

Ch. Heyn, A. Stemmann, and W. Hansen
We study the self-assembled local droplet etching of nanoholes in AlGaAs surfaces with Ga droplets. The data establish an unexpected delay of both the hole drilling process as well as the removal of the liquid material after etching. Furthermore, coarsening by Ostwald ripening is found to reduce the ... [Appl. Phys. Lett. 95, 173110 (2009)] published Wed Oct 28, 2009.

Observation of quantum-Hall effect in gated epitaxial graphene grown on SiC (0001)

T. Shen, J. J. Gu, M. Xu, Y. Q. Wu, M. L. Bolen et al.
Epitaxial graphene films examined were formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k gate stack on the epitaxial graphene was realized by inserting a fully oxidized nanometer thin aluminum film as a seeding layer, followed by an atomic ... [Appl. Phys. Lett. 95, 172105 (2009)] published Wed Oct 28, 2009.

Design and characterization of bubble phononic crystals

Valentin Leroy, Alice Bretagne, Mathias Fink, Herve Willaime, Patrick Tabeling et al.
We report the practical realization of phononic crystals with gas inclusions, using soft lithography techniques. Ultrasonic experiments from 0.3 to 5 MHz confirm the existence of deep and wide minima of transmission through the crystal. We show that the first gap is due to the combined effects of Br ... [Appl. Phys. Lett. 95, 171904 (2009)] published Wed Oct 28, 2009.

Growth of ultrathin film aluminum oxide on Ag(111)

S. Vizzini, H. Oughaddou, J. Y. Hoarau, J. P. Biberian, and B. Aufray
Scanning tunneling microscopy (STM) and spectroscopy and electron energy loss spectroscopy were used to characterize ultrathin epitaxial aluminum oxide on Ag(111) which was prepared via a specific deposition and oxidation process. Atomically resolved STM images show self-organized oxide stripes of 4 ... [Appl. Phys. Lett. 95, 173111 (2009)] published Wed Oct 28, 2009.

Anomalous Hall resistance in Ge:Mn systems with low Mn concentrations

Shengqiang Zhou (周生强), Danilo Burger, Manfred Helm, and Heidemarie Schmidt
Taking Mn doped Germanium as an example, we evoke the consideration of a two-band-like conduction in diluted ferromagnetic semiconductor (FMS). The main argument for claiming Ge:Mn as a FMS is the occurrence of the anomalous Hall effect (AHE). Usually, the reported AHE (1) is observable at temperatu ... [Appl. Phys. Lett. 95, 172103 (2009)] published Tue Oct 27, 2009.

Impact of high-order surface plasmon modes of metal nanoparticles on enhancement of optical emission

G. Sun, J. B. Khurgin, and C. C. Yang
We consider the impact of high-order surface plasmon modes supported by the metal nanoparticles on the efficiency enhancement of optical emission. Using the example of Au nanosphere embedded in the GaN dielectric, we show that for an emitter with certain original radiative efficiency, placing the em ... [Appl. Phys. Lett. 95, 171103 (2009)] published Tue Oct 27, 2009.

Interface and bulk magnetism of CoCrFeAl and CoCrAl thin films

Martin Jourdan, Elena Arbelo Jorge, Christian Herbort, Michael Kallmayer, Peter Klaer et al.
The interface and bulk magnetic properties of epitaxial thin films of the Heusler compounds CoCrFeAl/Mg/AlO and CoCrAl/Mg/AlO are investigated. We compare the magnetization measured by x-ray magnetic circular dichroism experiments in surface sensitive total electron yield mode (information depth of ... [Appl. Phys. Lett. 95, 172504 (2009)] published Tue Oct 27, 2009.

Strongly birefringent metamaterials as negative index terahertz wave plates

P. Weis, O. Paul, C. Imhof, R. Beigang, and M. Rahm
We report an alternative approach for the design and fabrication of thin wave plates with high transmission in the terahertz regime. The wave plates are based on strongly birefringent cut-wire-pair metamaterials that exhibit refractive indices of opposite signs for orthogonal polarization components ... [Appl. Phys. Lett. 95, 171104 (2009)] published Tue Oct 27, 2009.

Effects of hydration levels on the bandwidth of microwave resonant absorption induced by confined acoustic vibrations

Tzu-Ming Liu, Hung-Pin Chen, Shih-Chia Yeh, Chih-Yu Wu, Chung-Hsiung Wang et al.
We found the hydration levels on the capsid surface of viruses can affect the bandwidth of microwave resonant absorption (MRA) induced by the confined acoustic vibrations (CAV). By decreasing the pH value of solution down to 5.2 or inactivating the capsid proteins, we enhanced the surface hydrophili ... [Appl. Phys. Lett. 95, 173702 (2009)] published Tue Oct 27, 2009.

Anomalous scaling during glancing angle deposition

S. Mukherjee and D. Gall
Metallic nanorods grown by glancing angle deposition at T=3001123 K exhibit self-affine scaling, where the average rod width w increases with height h according to w[proportional]h. The growth exponent p for the investigated metals (Ta, Nb, and Cr) varies with temperature and material but collapses ... [Appl. Phys. Lett. 95, 173106 (2009)] published Tue Oct 27, 2009.

High optical quality InAs site-controlled quantum dots grown on soft photocurable nanoimprint lithography patterned GaAs substrates

Chien-Chia Cheng, K. Meneou, and K. Y. Cheng
InAs site-controlled quantum dots (SCQDs) have been demonstrated on GaAs substrates patterned by soft photocurable nanoimprint lithography. The substrates are patterned with a dense array of 100 nm nanopores and then InAs is deposited by molecular beam epitaxy to form uniform single QD in each patte ... [Appl. Phys. Lett. 95, 173108 (2009)] published Tue Oct 27, 2009.

Scanning tunneling microscopy with single crystalline W[001] tips: High resolution studies of Si(557)5 x 5 surface

A. N. Chaika, V. N. Semenov, V. G. Glebovskiy, and S. I. Bozhko
Single crystalline [001]-oriented tungsten tips have been applied for high resolution scanning tunneling microscopy (STM) studies of a Si(557) surface consisting of triple steps and 5 x 5-reconstructed Si(111) terraces. High stability of the W[001] tips allowed us to measure atomically resolved imag ... [Appl. Phys. Lett. 95, 173107 (2009)] published Tue Oct 27, 2009.

Controlling microstructure and magnetization process of FePd (001) films by staged thermal modification

D. H. Wei and Y. D. Yao
Staged thermal modifications on the microstructure and magnetic characterizations of epitaxial FePd films have been investigated, while the optimum composition for FePd (001) films with the highest ordering degree was FePd. For the FePd films directly grown at the low temperature of 400 degrees C, ... [Appl. Phys. Lett. 95, 172503 (2009)] published Tue Oct 27, 2009.

The effect of UV ozone treatment on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)

M. G. Helander, Z. B. Wang, M. T. Greiner, Z. W. Liu, K. Lian et al.
The interface between ultraviolet (UV) ozone treated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and N,N-diphenyl-N,N-bis-(1-naphthyl)-1-1-biphenyl-4,4-diamine (alpha-NPD) was investigated using single carrier hole-only devices and in situ ultraviolet and x-ray photoelectron ... [Appl. Phys. Lett. 95, 173302 (2009)] published Tue Oct 27, 2009.

Probing activation energy barrier distribution for reversal of strongly exchange-coupled magnetic multilayer thin films

O. Ozatay, T. Hauet, S. H. Florez, J. A. Katine, A. Moser et al.
We demonstrate a measurement technique with zero-applied magnetic field to deduce and spatially map the activation energy barrier distribution of strongly exchange-coupled magnetic-multilayer thin films, which is otherwise inaccessible with conventional methods in the presence of an applied magnetic ... [Appl. Phys. Lett. 95, 172502 (2009)] published Tue Oct 27, 2009.

Effect of substrate piezoelectricity on surface acoustic wave propagation in humidity-sensitive structures with porphyrin layers

D. Ciplys, R. Rimeika, A. Sereika, V. Poderys, R. Rotomskis et al.
The impact of air humidity on surface acoustic wave (SAW) propagation in different piezoelectric substrates (lithium niobate, lithium tantalate, and gallium nitride on sapphire) with nanostructured meso-tetra(4 sulfonatophenyl) porphyrin (TPPS) overlays has been investigated. The humidity-induced in ... [Appl. Phys. Lett. 95, 171903 (2009)] published Tue Oct 27, 2009.

Three-dimensional structure of the buffer/absorber interface in CdS/CuGaSe based thin film solar cells

M. Rusu, M. Bar, S. Lehmann, S. Sadewasser, L. Weinhardt et al.
The chemical structure of the CdS/CuGaSe chalcopyrite solar cell buffer/absorber interface is investigated by combining element depth profiling using elastic recoil detection analysis and surface-near bulk sensitive x-ray emission spectroscopy. Significant Cd and S concentrations (>=0.1 at. %) are ... [Appl. Phys. Lett. 95, 173502 (2009)] published Tue Oct 27, 2009.

Two-dimensional growth of SrTiO thin films on (001) MgO substrates using pulsed laser deposition and reflection high energy electron diffraction

S. R. C. McMitchell, Y. Y. Tse, H. Bouyanfif, T. J. Jackson, I. P. Jones et al.
Two-dimensional epitaxial growth of SrTiO is achieved on MgO, a substrate presenting a large lattice mismatch of 7.9%. In situ reflection high energy electron diffraction (RHEED) is used to monitor and control the growth. An interval deposition technique is implemented to force the two-dimensional g ... [Appl. Phys. Lett. 95, 174102 (2009)] published Mon Oct 26, 2009.

Transparent and flexible polymerized graphite oxide thin film with frequency-dependent dielectric constant

D. W. Lee, J. W. Seo, G. R. Jelbert, L. de Los Santos, V., J. M. Cole et al.
Here we report on the preparation of transparent and flexible polymerized graphite oxide, which is composed of carbons with sp-hybridized orbitals and a nonplanar ring structure, and which demonstrates dispersion in its dielectric constant at room temperature. This frequency dependence renders the m ... [Appl. Phys. Lett. 95, 172901 (2009)] published Mon Oct 26, 2009.

Switchable fluorescent liquid crystals

M. Salamonczyk, A. Kovarova, J. Svoboda, D. Pociecha, and E. Gorecka
Properties of new fluorescent, mesogenic compounds bearing [2]benzothiophene moiety are presented. Materials show strong fluorescence of green or red light with quantum yield up to 30%, in liquid crystalline phases the emitted light is strongly polarized. For material forming ferroelectric liquid cr ... [Appl. Phys. Lett. 95, 171901 (2009)] published Mon Oct 26, 2009.

Magnetization-controlled conductance in (Ga,Mn)As-based resonant tunneling devices

M. Tran, J. Peiro, H. Jaffres, J.-M. George, O. Mauguin et al.
We report on experimental evidence of a magnetization-controlled conductance in AlAs/GaAs/AlAs resonant tunneling diodes contacted by a (Ga,Mn)As ferromagnetic electrode. Large shifts of the resonance voltages occur as the magnetization is rotated from in-plane to out-of-plane directions resulting i ... [Appl. Phys. Lett. 95, 172101 (2009)] published Mon Oct 26, 2009.

Regular surface grating on doped polymer induced by laser scanning

Oleksiy Lyutakov, Ivan Huttel, Jakub Siegel, and Vaclav SvorCik
Thin polymer film doped with optical chromophore porphyrin are shown to respond to irradiation with laser light (lambda=405 nm). By simultaneous scanning with laser beam and continual mechanical movement of the polymer film regular grating pattern is formed on the polymer surface. Parameters of the ... [Appl. Phys. Lett. 95, 173103 (2009)] published Mon Oct 26, 2009.

Electrical spin injection into Si(001) through a SiO tunnel barrier

C. H. Li, G. Kioseoglou, O. M. J. van `t Erve, P. E. Thompson, and B. T. Jonker
We demonstrate spin polarized tunneling from Fe through a SiO tunnel barrier into a Si n-i-p heterostructure. Transport measurements indicate that single step tunneling is the dominant transport mechanism. The circular polarization P of the electroluminescence shows that the tunneling spin polarizat ... [Appl. Phys. Lett. 95, 172102 (2009)] published Mon Oct 26, 2009.

Otto-coupled surface plasmons in a liquid crystal cell

Lizhen Ruan, Fuzi Yang, and J. R. Sambles
Surface plasmons on silver in the visible domain are excited using a several micron thick layer of liquid crystal as the optical tunnel barrier. This thickness is possible when the orientation of the director in the liquid crystal varies from homeotropic at the entrance surface (against the coupling ... [Appl. Phys. Lett. 95, 171102 (2009)] published Mon Oct 26, 2009.

Microwave transmissivity of a metamaterialdielectric stack

Celia A. M. Butler, James Parsons, J. Roy Sambles, Alastair P. Hibbins, and Peter A. Hobson
A metamaterial layer comprising of a conducting square mesh surrounding subwavelength holes has a largely pure imaginary effective refractive index. We explore the microwave transmissivity of a stack of such metamaterial layers separated by dielectric spacers. As expected, a family of high transmiss ... [Appl. Phys. Lett. 95, 174101 (2009)] published Mon Oct 26, 2009.

Charge-transfer induced surface conductivity for a copper based inorganic-organic hybrid

Anne H. Arkenbout, Takafumi Uemura, Jun Takeya, and Thomas T. M. Palstra
Inorganic-organic hybrids are receiving increasing attention as they offer the opportunity to combine the robust properties of inorganic materials with the versatility of organic compounds. We have studied the electric properties of an inorganic-organic hybrid with the chemical formula: CuCl(CHCHCHN ... [Appl. Phys. Lett. 95, 173104 (2009)] published Mon Oct 26, 2009.

Thermal annealing induced bicontinuous networks in bulk heterojunction solar cells and bipolar field-effect transistors

Hoyoul Kong, Ji Sun Moon, Nam Sung Cho, In Hwan Jung, Moo-Jin Park et al.
Polymer bulk heterojunction solar cells fabricated from poly(2,5-bis(3-dodecyl-2,2-bithiophen-5-yl)-3,6-dimethylthieno [3,2-b] thiophene):[6,6]-phenyl-C-butric acid methyl ester (1:1, w/w) blend showed significantly improved power conversion efficiency (PCE), from 0.96% to 2.32%, with post-thermal a ... [Appl. Phys. Lett. 95, 173301 (2009)] published Mon Oct 26, 2009.

Addressable photocharging of single quantum dots assisted with atomic force microscopy probe

M. Dokukin, R. Olac-Vaw, N. Guz, V. Mitin, and I. Sokolov
Here we report on addressable photocharging of individual cadmium selenide quantum dots (QDs). The charging is a result of synergetic action of light and an atomic force microscope (AFM) probe. The probe squeezes the coating layer of QDs helping the photoelectron to tunnel to either conductive AFM p ... [Appl. Phys. Lett. 95, 173105 (2009)] published Mon Oct 26, 2009.

Enhanced room-temperature quantum-dot effects in modulation-doped InAs/GaAs quantum dots

Y. D. Jang, J. Park, D. Lee, D. J. Mowbray, M. S. Skolnick et al.
Modulation-doped InAs/GaAs quantum dots (QDs) show bright photoluminescence (PL) at 300 K, linear increase of PL intensity on excitation at 300 K and rather temperature insensitive PL intensity and carrier lifetime, in contrast to undoped QDs. Systematic analyses indicate that those advantageous beh ... [Appl. Phys. Lett. 95, 171902 (2009)] published Mon Oct 26, 2009.

Scalable arrays of rf Paul traps in degenerate Si

J. Britton, D. Leibfried, J. A. Beall, R. B. Blakestad, J. H. Wesenberg et al.
We report techniques for the fabrication of multizone linear radio frequency Paul traps that exploit the machinability and electrical conductivity of degenerate silicon. The approach was tested by trapping and laser cooling Mg ions in the two following trap geometries: a single-zone two-layer trap a ... [Appl. Phys. Lett. 95, 173102 (2009)] published Mon Oct 26, 2009.

Relaxation and emittance growth of a thermal charged-particle beam

Tarcisio N. Teles, Renato Pakter, and Yan Levin
We present a theory that allows us to accurately calculate the distribution functions and the emittance growth of a thermal charged-particle beam after it relaxes to equilibrium. The theory can be used to obtain the fraction of particles, which will evaporate from the beam to form a halo. The calcul ... [Appl. Phys. Lett. 95, 173501 (2009)] published Mon Oct 26, 2009.

Coupling an epitaxial quantum dot to a fiber-based external-mirror microcavity

Andreas Muller, Edward B. Flagg, Michael Metcalfe, John Lawall, and Glenn S. Solomon
We report the coupling of individual InAs quantum dots (QDs) to an external-mirror microcavity. The external mirror is bonded to a fiber and positioned above a semiconductor sample consisting of a QD-containing GaAs layer on top of a distributed Bragg reflector. This open cavity can be rapidly tuned ... [Appl. Phys. Lett. 95, 173101 (2009)] published Mon Oct 26, 2009.

Coherent emission from large arrays of discrete Josephson junctions

F. Song (宋凤斌), F. Muller, R. Behr, and A. M. Klushin
We observed coherent emission at the frequency of 76 GHz from a large-area array of 7500 niobium junctions embedded in the quasioptical resonator at liquid helium temperature. The maximal detected power of 2 [mu]W was measured by a room temperature superheterodyne receiver. To explain the coherent ... [Appl. Phys. Lett. 95, 172501 (2009)] published Mon Oct 26, 2009.

A room temperature 19-channel magnetic field mapping device for cardiac signals

G. Bison, N. Castagna, A. Hofer, P. Knowles, J.-L. Schenker et al.
We present a multichannel cardiac magnetic field imaging system built in Fribourg from optical double-resonance Cs vapor magnetometers. It consists of 25 individual sensors designed to record magnetic field maps of the beating human heart by simultaneous measurements on a grid of 19 points over the ... [Appl. Phys. Lett. 95, 173701 (2009)] published Mon Oct 26, 2009.

Refractive index dispersion deduced from lasing modes in ZnO microtetrapods

V. V. Ursaki, V. V. Zalamai, I. M. Tiginyanu, A. Burlacu, E. V. Rusu et al.
High optical quality, well end leg faceted ZnO microtetrapods sustaining lasing modes with quality factors of 25003000 have been grown by carbothermal chemical vapor deposition. It is shown that lasing is due to longitudinal FabryPerot modes in individual tetrapod legs and the analysis of the wavele ... [Appl. Phys. Lett. 95, 171101 (2009)] published Mon Oct 26, 2009.