Tunneling modulation of a quantum-well transistor laser
Different than the Bardeen and Brattaintransistor (1947) with thecurrent gain depending on the ratio of the base carrier spontaneous recombination lifetime to the emitter-collector transit time, the Feng and Holonyaktransistor lasercurrent gain depends upon the base electron-hole (e-h) stimulated recombination, the basedielectric relaxation transport, and the collector stimulatedtunneling. For the n-p-ntransistor lasertunneling operation, the electron –hole pairs are generated at the collector junction under the influence of intra-cavity photon-assistedtunneling, withelectrons drifting to the collector and holes drifting...
Source: Journal of Applied Physics - November 22, 2016 Category: Physics Authors: M. Feng, J. Qiu, C. Y. Wang and N. Holonyak Jr. Source Type: research
THz conductivity of semi-insulating and magnetic CoFe2O4 nano-hollow structures through thermally activated polaron
Herein, terahertz (THz) time domainspectroscopy is used to measure the complex conductivity of semi-insulating CoFe2O4 nanoparticles (NPs) and nano-hollow spheres (NHSs) with different diameters ranging from 100 to 350 nm having a nanocrystalline shell thickness of 19 to 90 nm, respectively. Interestingly, the magnitude of conductivity for CoFe2O4 NPs and NHSs of same average diameter ( ∼100 nm) for a given frequency of 0.3 THz is found to be 0.33 S/m and 9.08 S/m, respectively, indicating that the hollowstructure exhibits greater THz conduction in comparison to its solid counterpart. Moreover, THz conductivit...
Source: Journal of Applied Physics - November 22, 2016 Category: Physics Authors: Rupali Rakshit, Kazunori Serita, Masayoshi Tonouchi and Kalyan Mandal Source Type: research
Plasmonic switching and bistability at telecom wavelength using the subwavelength nonlinear cavity coupled to a dielectric waveguide: A theoretical approach
Theoretical investigation of optical switching in aplasmonicdevice comprising a metal-dielectric-metalwaveguide perpendicularly coupled to a single nanocavity is reported. Thecavity is filled with a third ordernonlinearKerrmaterial whose optical properties are manipulated using a control beam to trigger the switching operation. The performance of the switch is quantitatively evaluated and compared with other switching mechanisms used in a similarplasmonic structure. The comparative study reveals that the efficiency of ourplasmonic switch is many folds higher and hence advantageous over absorption switching. The dependence ...
Source: Journal of Applied Physics - November 22, 2016 Category: Physics Authors: S. Paul and M. Ray Source Type: research
Wideband long wave infrared metamaterial absorbers based on silicon nitride
In this paper, we presentsilicon nitridemetamaterial absorber designs that accomplish large bandwidth and highabsorption in the long wave infrared (LWIR) region. These designs are based on the metal-insulator-metaltopology, insulator(silicon nitride), and the top metal (aluminum) layers are optimized to obtain high absorptance values in large bandwidths, for three differentsilicon nitride based absorber structures. Theabsorptionspectrum of the final design reaches absorptance values above 90% in the wavelength interval between 8.07 μm and 11.97 μm, and above 80% in the wavelength interval between 7.9 μm and 14 ...
Source: Journal of Applied Physics - November 22, 2016 Category: Physics Authors: Kadir Üstün and Gönül Turhan-Sayan Source Type: research
Physical investigation of electrophoretically deposited graphene oxide and reduced graphene oxide thin films
Graphene oxide and reducedgraphene oxidethin films are very promising materials because they can be used in optoelectronic devices and in a growing range of applications such as touch screens and flexible displays. In this work,graphene oxide (GO) and thermally reducedgraphene oxide (rGO)thin films,deposited on Ti/glass substrates, have been obtained byelectrophoreticdeposition. The morphological and thestructural properties of the samples have been investigated by micro-Raman technique,X-ray reflectometry, and SEM analysis. In order to study the optical and electrical properties, variable angle spectroscopic ellipsometry ...
Source: Journal of Applied Physics - November 21, 2016 Category: Physics Authors: Grazia Giuseppina Politano, Carlo Versace, Carlo Vena, Marco Castriota, Federica Ciuchi, Angela Fasanella, Giovanni Desiderio and Enzo Cazzanelli Source Type: research
An influence of the local strain on cathodoluminescence of GaN/AlxGa1 −xN nanowire structures
Near-band-edge excitonic emission shift is investigated as a measure of the local strain inGaNnanowires with single AlxGa1 −xN sections of various Al contents (x = 0.0, 0.22, 0.49, 1.0). Complementary data obtained by spatially and spectrally resolvedcathodoluminescence spectroscopy and imaging of individualnanowires at low temperature, high resolutionX-ray diffraction, and transmission electron microscopy are used to determine the correspondence between thecathodoluminescence emission energy and the strain in theGaN core of thenanowire surrounded by the AlxGa1 −xN shell formed during the growth of AlxGa1 −xN se...
Source: Journal of Applied Physics - November 21, 2016 Category: Physics Authors: Anna Reszka, Aleksandra Wierzbicka, Kamil Sobczak, Uwe Jahn, Ute Zeimer, Andrian V. Kuchuk, Agnieszka Pieni ążek, Marta Sobanska, Kamil Klosek, Zbigniew R. Zytkiewicz and Bogdan J. Kowalski Source Type: research
Understanding electrical-thermal transport characteristics of organic semiconductors: Violation of Wiedemann-Franz law
Organic semiconductors exhibit plenty of attractiveproperties for use as thermoelectric elements. A comprehensive understanding for the electrical-thermaltransportcharacteristics is crucial to design and fabricate the thermoelectric device. We proposed a theoretical model to investigate the electrical conductivity and the electronicthermal conductivity oforganic semiconductors based on thehopping transport mechanism. The electrical-thermaltransportcharacteristics oforganic semiconductors have been analyzed in detail and compared with the experimental results and Monte Carlo simulation. The Wiedemann-Franz law, connecting t...
Source: Journal of Applied Physics - November 21, 2016 Category: Physics Authors: Nianduan Lu, Ling Li, Nan Gao and Ming Liu Source Type: research
Strain control of vibrational properties of few layer phosphorene
Usingdensity functional theory techniques, we study lattice vibrational Raman and infrared modes in strained few-layer phosphorene. We find very significant frequency shifts, up to≈ 100 cm−1 in the applied strain range of ±6%, of the Raman activities in both high- and low-frequency region and infrared activities in the low-frequency region. The type of applied strain, that is, armchair and zigzag, selectively affects specific vibrational modes. Combined with high spatial-resolution Raman/infrared scattering experime nts, our calculated results can aid understanding of the complicated inhomogeneous strain distribut...
Source: Journal of Applied Physics - November 21, 2016 Category: Physics Authors: K. Tok ár, R. Derian, J. Brndiar and I. Štich Source Type: research
Plasma formation in diode pumped alkali lasers sustained in Cs
Indiode pumped alkali lasers (DPALs), lasing action occurs on the resonant lines of alkali atoms followingpumping by broadband semiconductor lasers. The goal is to convert the efficient but usually poor optical quality of inexpensivediode lasers into the high optical quality of atomic vapor lasers. Resonant excitation of alkali vapor leads toplasma formation through the excitation transfer from the2P states to upper lying states, which then are photoionized by the pump and intracavity radiation. A first principles global model was developed to investigate the operation of the He/Cs DPAL system and the consequences ofplasma...
Source: Journal of Applied Physics - November 21, 2016 Category: Physics Authors: Aram H. Markosyan and Mark J. Kushner Source Type: research
Understanding the basic concepts of CO2 angiography
The diagnostic quality ofcarbon dioxideangiography depends both on optimal setting of radiological aspects(X-ray emission andimage post-processing) and on the mechanical behavior of the injected gas bubbles. The gas behavior differs in large cavities (d > 12 mm), medium sized vessels (d > 6 mm), and small diameter vessels (d (Source: Journal of Applied Physics)
Source: Journal of Applied Physics - November 21, 2016 Category: Physics Authors: Romano Zannoli, David Bianchini, Pier Luca Rossi, James G. Caridi and Ivan Corazza Source Type: research
Charge neutral MoS2 field effect transistors through oxygen plasma treatment
In this study, we demonstrate a simple and reliable oxygenplasma treatment, which mitigates the effects of unintentional doping created by surface defect sites, such as Svacancies, and surface contamination. Thisplasma treatment restores charge neutrality to the MoS2 and shifts the threshold turn-on voltage towards 0 V. Out of the 10devices measured, all exhibit a shift of theFET turn-on voltage from an average of −18 V to −2 V. The oxygenplasma treatment passivates these defects, which reducessurface scattering, causing increasedmobility and improved subthreshold swing. For as-prepareddevices with lowmobilities...
Source: Journal of Applied Physics - November 18, 2016 Category: Physics Authors: Rohan Dhall, Zhen Li, Ewa Kosmowska and Stephen B. Cronin Source Type: research
Atomic scale analysis of phase formation and diffusion kinetics in Ag/Al multilayer thin films
Thin films generally exhibit unusual kinetics leading to chemical reactions far from equilibrium conditions. Binary metallicmultilayerthin films with miscible elements show some similar behaviors with respect tointerdiffusion and phase formation mechanisms. Interfacial density, lattice defects, internal stresses, layer morphologies anddeposition conditions strongly control the mass transport between the individual layers. In the present work, Ag/Almultilayerthin films are used as a simple model system, in which the effects of thesputtering power and the bilayer period thickness on theinterdiffusion and film reactions are i...
Source: Journal of Applied Physics - November 18, 2016 Category: Physics Authors: Hisham Aboulfadl, Isabella Gallino, Ralf Busch and Frank M ücklich Source Type: research
Improvement of optical and electric characteristics of MoO3/Ag film/MoO3 flexible transparent electrode with metallic grid
In this paper, the authors report rationally designed, innovative tri-layer flexible transparent conductiveelectrodes (TCEs) fabricated via thermaldeposition. The proposed structure improves transparency compared with that of the traditional tri-layerelectrode (dielectric/metal film/dielectric) by using metallic grid patterns (dielectric/metal grids/dielectric). The obtained MoO3/Ag grids/MoO3 TCEs show low sheet resistance and goodmechanical properties. The sheet resistance of the proposedelectrodes is 5.88 Ω/square and the transmittance reaches 76.5%, which are better than those of conventional MoO3/Ag film/MoO3elect...
Source: Journal of Applied Physics - November 18, 2016 Category: Physics Authors: Chen-Tao Wang, Chu-Chi Ting, Po-Ching Kao, Shan-Rong Li and Sheng-Yuan Chu Source Type: research
A study on Si/Al2O3 paramagnetic point defects
In this contribution, negative charges and electronic traps related to theSi/Al2O3interface were measured and related toparamagnetic point defects and molecular vibrations. To this end, contactless capacitance voltage measurements, X-bandelectron paramagnetic resonance(EPR), and infrared spectroscopy were carried out, and their results were compared. A change in the negative charge density and electron trap density at theSi/Al2O3interface was achieved by adding a thermally grownSiO2 layer with varying thicknesses and conducting an additional temperature treatment. UsingEPR, fiveparamagnetic moments were detected inSi/(SiO2...
Source: Journal of Applied Physics - November 18, 2016 Category: Physics Authors: S. K ühnhold-Pospischil, P. Saint-Cast, M. Hofmann, S. Weber, P. Jakes, R.-A. Eichel and J. Granwehr Source Type: research
Investigation of pitting corrosion of diamond-like carbon films using synchrotron-based spectromicroscopy
Corrosion behavior of diamond-likecarbon (DLC)films was evaluated via potentiodynamicpolarization in a 3.5 wt. % NaCl solution with pH 2 at room temperature. Thepolarization results elucidated that thecorrosion resistance of thefilms was enhanced with the variation of the chemical compositions andfilm thicknesses. The use of the spectromicroscopy method in the investigation of the pittingcorrosion was a success in this study. Formation of orbital mapping, bonding state, and composition of the DLCfilms at non-corrosion andcorrosion areas indicate the differentstructures between DLC and graphite oxide. Also, the π* (C=C)...
Source: Journal of Applied Physics - November 18, 2016 Category: Physics Authors: Sarayut Tunmee, Pat Photongkam, Chanan Euaruksakul, Hiroki Takamatsu, XiaoLong Zhou, Pornwasa Wongpanya, Keiji Komatsu, Kazuhiro Kanda, Haruhiko Ito and Hidetoshi Saitoh Source Type: research
