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Presents a study which examined highly carbon-doped gallium arsenide epilayers grown by low-pressure metalorganic vapor phase epitaxy using high-resolution x-ray diffraction. Information on carbon-doping; Methodology; Results.

Focuses on a study which presented a photoluminescence (PL) analysis of gallium indium phosphide/gallium arsenide single-quantum well structures grown by metal-organic vapor-phase epitaxy. Description of the sample and procedure; Estimation of the growth temperature dependent conduction and valence band discontinuity of the heterojunction; Results of x-ray diffraction measurements and simulations.

Deals with a study that investigated the use of thin film technology to introduce controllable and thermally stable stress into semiconductor heterostructures. Reason for the reproducibility and controllability of the induced stress in the structure; Dependence of the stability of the stress; Interrelationship between the photoelastic waveguide characteristics and the stress.

Presents a study that investigated gallium compound interfaces grown by low-pressure metalorganic vapor phase epitaxy at various temperatures and in different structures. Use of photoluminescence method; Results of the examination on gallium compound using x-ray diffraction measurements and simulations with dynamical theory.

Studies the use of high resolution x-ray diffraction thin indium arsenide and gallium arsenide layers grown on InP substrates by low-pressure metalorganic vapor-phase epitaxy. Growth parameter and structural parameter of the investigated samples; Superlattice periods determined from the observed satellites separations; Enlargement of an experimental rocking curve of sample IX in the vicinity of the zeroth-order peak.

Investigates single-element contracts, palladium or nickel, on various p-InP susbstrates grown by liquid-encapsulation Czochralski and by metal-organic chemical vapor deposition. Procedures used to evaluate the substrates; Factor responsible for the observed difference in ohmic behavior; Description of the proposed defect-assisted tunneling mechanism.

Focuses on a study which described the use of elevated temperature implantation to simultaneously achieve compositional disordering and electrical isolation and form guided-wave modulators using oxygen ion beam mixing. Insight on indium phosphide (InP)-based ion-beam mixing devices; Description of results on elevated temperature oxygen ion beam mixing in InP-based superlattices; Discussion on the photoelastic effect in InP-based structures.

By micromagnetic simulation, we investigated a double 360° domain walls system in two parallel nanowires. Two domain walls are coupled to each other via magnetostatic interaction. When a spin-polarized current is applied to only one nanowire or both nanowires with the same direction, the two domain walls propagate along nanowires together. The critical velocity of such system is obviously higher than that of a single 360° domain wall. The interaction between the two domain walls can be modeled as two bodies that connected by a spring, and we analyzed the coupling characteritics of the double 360° domain walls at last. [ABSTRACT FROM AUTHOR]

Dy doped α-SiAlON ceramics prepared by the hot-pressing method show a high optical transmittance value, >70%, in the infrared region of 1.5–4.5 μm. First principles calculations have been carried out to reveal the underlying transparency mechanism. It is found that the valence shell of doped Dy atoms interacts strongly with the doping states of α-SiAlON, resulting in the increase in the optical gap from 0.4 to 1.1 eV, which suppresses the photoabsorption in the wavelength region longer than 1.0 μm and leads to the good transparency property. The calculated optical transmission spectra are in good agreement with the corresponding experiments. [ABSTRACT FROM AUTHOR]

We report that (La0.07Ba0.93)SnO3 films grown epitaxially on SrTiO3(001) substrates by laser ablation at 760 °C show a cubic perovskite structure of lattice constant 4.121 Å, excellent optical transmittance in the visible range, and a weak metallic behavior with low resistivity of about 4 mΩ cm within 10–300 K. The transparent perovskite oxide films are n-type conductors, with carrier concentration and mobility at room temperature of about 2×1021 cm-3 and 0.69 cm2/V s, respectively, and a direct allowed band gap of 4.02 eV. The effect of deposition temperature on structural, optical, and electric properties of the Sb-doped Ba(Sn0.93Sb0.07)O3 films was also demonstrated. [ABSTRACT FROM AUTHOR]

We report that (La0.07Ba0.93)SnO3 films grown epitaxially on SrTiO3(001) substrates by laser ablation at 760 °C show a cubic perovskite structure of lattice constant 4.121 Å, excellent optical transmittance in the visible range, and a weak metallic behavior with low resistivity of about 4 mΩ cm within 10–300 K. The transparent perovskite oxide films are n-type conductors, with carrier concentration and mobility at room temperature of about 2×1021 cm-3 and 0.69 cm2/V s, respectively, and a direct allowed band gap of 4.02 eV. The effect of deposition temperature on structural, optical, and electric properties of the Sb-doped Ba(Sn0.93Sb0.07)O3 films was also demonstrated. [ABSTRACT FROM AUTHOR]

M-type strontium hexaferrites of Sr1−xLaxFe12−xMnxO19 (0.0≤x≤0.4) were synthesized by the chemical coprecipitation method. X-ray diffraction (XRD) studies indicate that the samples are single-phase with the space group of P63/mmc. The results of field-emission scanning electronic microscopy (FE-SEM) show that the grains are regular hexagonal platelets with sizes from 0.7 to 1.4 μm. It is observed that the value of Hc increases at low substitution (x ≤ 0.1), reaches a maximum at x = 0.1 and then decreases at x ≥ 0.1, while the value of Ms decreases monotonously with increasing x. The variations of magnetic properties can be tentatively attributed to the effects of La–Mn substitutions. The results above indicate that our samples might be promising candidates for permanent magnets in the future. [ABSTRACT FROM AUTHOR]

We have compared the spin orbit torque (SOT) induced magnetization switching in Pt/Co/Pt/ Y3Fe5O12 (YIG) and Pt/Co/Pt/SiO2 multilayers. The critical switching current in Pt/Co/Pt/YIG is almost half of that in Pt/Co/Pt/SiO2. Through harmonic measurements, we demonstrated the enhancement of the effective spin Hall angle in Pt/Co/Pt/YIG. The increased efficiency of SOT is ascribed to the nonequilibrium proximity effect at the Pt/YIG interface, which suppresses the spin current reflection and enhances the effective spin accumulation at the Co/Pt interface. Our method can effectively reduce the switching current density and provide another way to modulate SOT. [ABSTRACT FROM AUTHOR]

In classical mechanics, a nonrelativistic particle constrained on an N — 1 curved hypersurface embedded in N flat space experiences the centripetal force only. In quantum mechanics, the situation is totally different for the presence of the geometric potential. We demonstrate that the motion of the quantum particle is ”driven” by not only the centripetal force, but also a curvature induced force proportional to the Laplacian of the mean curvature, which is fundamental in the interface physics, causing curvature driven interface evolution. [ABSTRACT FROM AUTHOR]

Design of head interconnect is one of the important issues for hard disk drives with higher data rate and storage capacity. The impedance of interconnect and electromagnetic coupling influence the quality level of data communication. Thus an insightful study on how the trace configuration affects the impedance and crosstalk is necessary. An effective design approach based on Taguchi's robust design method is employed therefore in an attempt to realize impedance matching and crosstalk minimization with the effects of uncontrollable sources taken into consideration. [ABSTRACT FROM AUTHOR]

We report the crystal structure and magnetic properties of the Zn1-xMnxO compounds synthesized by a combustion method. The Zn1-xMnxO compounds with x=0–0.1 crystallize in the wurtzite ZnO structure. The lattice parameters a and c of Zn1-xMnxO increase linearly with the Mn content, indicating that Mn2+ ions substitute for Zn2+ ions. Scanning electron microscopy shows that the average particle radius of Zn0.95Mn0.05O is about 40 nm. From the Curie–Weiss behavior of susceptibility at high temperature, it was found that the Mn–Mn interaction is dominated by antiferromagnetic coupling with effective nearest-neighbor exchange constant J about -32 K and the large negative value of the Curie–Weiss temperature. [ABSTRACT FROM AUTHOR]

The crystal structure and superconducting properties of RuSr[sub 2-x]Ba[sub x]GdCu[sub 2]O[sub 8] (0<=x<=0.1) have been investigated. X-ray powder diffraction (XRD) patterns show that the solid solution range is 0<=x<=0.1. The superconducting transition temperature was raised up to 35 K (zero) and 62 K (onset) for x=0.07, from 16 K (zero) and 45 K (onset) for x=0.0, and then T[sub C] decreases with x when x>0.07. Rietveld refinement for XRD data of RuSr[sub 2-x]Ba[sub x]GdCu[sub 2]O[sub 8] show that the apical Cu–O(1) bond length increases with an increase of x, while the Ru–O(1) bond length decreases, This may account for the enhancement of the superconducting transition temperature. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Considering its high carrier mobility and high saturation velocity, a low-noise amplifier is thought of as being the most attractive analogue application of graphene field-effect transistors. The noise performance of graphene field-effect transistors at frequencies in the K-band remains unknown. In this work, the noise parameters of a graphene transistor are measured from 10 to 26 GHz and noise models are built with the data. The extrinsic minimum noise figure for a graphene transistor reached 1.5 dB, and the intrinsic minimum noise figure was as low as 0.8 dB at a frequency of 10 GHz, which were comparable with the results from tests on Si CMOS and started to approach those for GaAs and InP transistors. Considering the short development time, the current results are a significant step forward for graphene transistors and show their application potential in high-frequency electronics. [ABSTRACT FROM AUTHOR]

A Darboux transformation is constructed for the generalized Hirota-Satsuma coupled KdV system and the result is compared with the recent work of Geng and his collaborators [X. G. Geng et al., Phys. Rev. E 79, 056602 (2009) and X. G. Geng and G. L. He, J. Math. Phys. 51, 033514 (2010)]. It is shown that our Darboux transformation may be applied to three interesting reductions of the general system. In addition, the iteration of this Darboux transformation is worked out, and some solutions to the associated systems are obtained. [ABSTRACT FROM AUTHOR]

The bulk Ca2CrO4 samples were synthesized under high pressure and high temperature conditions using CaO and CrO2 as starting materials. The structure of the prepared Ca2CrO4 solid is characterized by X-ray diffraction with Rietveld refinement as tetragonal structure with the space group I41/acd. The CrO6 octahedrons elongate along c axis and rotate in ab plane. DC and AC magnetic susceptibility measurement results indicate spin glass behavior at low temperature. Temperature dependence of resistivity measurement results show Ca2CrO4 is an insulator at both ambient condition and high pressure. [ABSTRACT FROM AUTHOR]

A thermally enhanced magnetoresistance (ThMR) was designed and obtained by simultaneously applying charge and heat currents to a NiFe thin film. From the measurement we observed that the magnetoresistance value was as high as -22600% when the input charge current and applied temperature gradient was 0.966 µA and 2.5 °C/mm, respectively. This ThMR can be controllable by adjusting the relative values of the input charge and heat currents. On increasing the input charge current from 0.85 to 1.05 µA by fixing the temperature gradient at 2.5 °C/mm, the ThMR first increased from 9% to 183% and then decreased from -259% to -13%, at intervals of ~0.96 µA. This can be explained by the spin-dependent transport phenomenon i.e., scattering induced sign difference between magnetoresistance and magnetothermopower in NiFe. [ABSTRACT FROM AUTHOR]

Quasi-free-standing epitaxialgraphenegrown on wide band gap semiconductorSiC demonstrates high carrier mobility and good material uniformity, which make it promising for graphene-based electronic devices. In this work, quasi-free-standing bilayer epitaxialgraphene is prepared and its transistors with gate lengths of 100 nm and 200 nm are fabricated and characterized. The 100 nm gate length graphenetransistor shows improved DC and RF performances including a maximum current density Ids of 4.2 A/mm, and a peak transconductance gm of 2880 mS/mm. Intrinsic current-gain cutoff frequency fT of 407 GHz is obtained. The exciting DC and RF performances obtained in the quasi-free-standing bilayer epitaxialgraphenetransistor show the great application potential of this material system. [ABSTRACT FROM AUTHOR]

To investigate light emission and dynamic deformation behaviors, sapphire (single crystal Al2O3) samples with three crystallographic orientations (a, c, and r-cut) were shock-compressed by the planar impact method, with final stress ranges from 47 to 65 GPa. Emission radiance and velocity versus time profiles were simultaneously measured with a fast pyrometer and a Doppler pin system in each experiment. Wave profile results show anisotropic elastic-plastic transitions, which confirm the literature observations. Under final shock stress of about 52 GPa, lower emission intensity is observed in the r-cut sample, in agreement with the previous report in the literature. When final shock stress increases to 57 GPa and 65 GPa, spectral radiance histories of the r-cut show two stages of distinct features. In the first stage, the emission intensity of r-cut is lower than those of the other two, which agrees with the previous report in the literature. In the second stage, spectral radiance of r-cut increases with time at much higher rate and it finally peaks over those of the a and c-cut. These observations (conversion of intensified emission in the r-cut) may indicate activation of a second slip system and formation of shear bands which are discussed with the resolved shear stress calculations for the slip systems in each of the three cuts under shock compression. [ABSTRACT FROM AUTHOR]

The complex refractive index of graphene fabricated using chemical vapor deposition is characterized at 1550 nm wavelength through the reflectivity measurement on a SiO2/Si substrate. The observed tunability of the complex reflective index as the function of gate electric voltage is in agreement with the prediction based on the Kubo formula. [ABSTRACT FROM AUTHOR]

Love mode surface acoustic wave (SAW) sensors have been recognized as one of the most sensitive devices for gravimetric sensors in liquid environments such as bio sensors. Device operation is based upon measuring changes in the transmitted (S21) frequency and phase of the first-order Love wave resonance associated with the device upon on attachment of mass. However, temperature variations also cause a change in the first order S21 parameters. In this work, shallow grooved reflectors and a "dotted" single phase unidirectional interdigitated transducer (D-SPUDT) have been added to the basic SAW structure, which promote unidirectional Love wave propagation from the device's input interdigitated transducers. Not only does this enhance the first-order S21 signal but also it allows propagation of a third-order Love wave. The attenuation coefficient of the third-order wave is sufficiently great that, whilst there is a clear reflected S11 signal, the third-order wave does not propagate into the gravimetric sensing area of the device. As a result, whilst the third-order S11 signal is affected by temperature changes, it is unaffected by mass attachment in the sensing area. It is shown that this signal can be used to remove temperature effects from the first-order S21 signal in real time. This allows gravimetric sensing to take place in an environment without the need for any other temperature measurement or temperature control; this is a particular requirement of gravimetric biosensors. [ABSTRACT FROM AUTHOR]

The effect of polarization fatigue on the Rayleigh coefficients of ferroelectric lead zirconate titanate (PZT) thin film was systematically investigated. It was found that electrical fatigue strongly affects the Rayleigh behaviour of the PZT film. Both the reversible and irreversible Rayleigh coefficients decrease with increasing the number of switching cycles. This phenomenon is attributed to the growth of an interfacial degraded layer between the electrode and the film during electrical cycling. The methodology used in this work could serve as an alternative way for evaluating the fatigue endurance and degradation in dielectric properties of ferroelectric thin-film devices during applications [ABSTRACT FROM AUTHOR]

The hydrogenated nanocrystalline silicon (nc-Si:H) films have been fabricated as resistiveswitching medium by radio frequency plasma enhanced chemical vapor deposition technology. The constructed Ag/nc-Si:H/Pt structure exhibits stable three nonvolatile resistance states. Tristateresistive states with large ratio 10² and 105, less variation of resistance, and long retentionexceeding 2.3 x 105s are observed in Ag/nc-Si:H/Pt stack. The temperature dependence of highresistance state (HRS) and intermediate resistance state (IRS) both show semiconductor behavior, and the temperature dependence of low resistance state (LRS) represents metallic property. Fittingresults demonstrated that the conduction mechanism of HRS, IRS, and LRS showed space chargelimited conduction (SCLC), tunneling, and ohmic characteristics, respectively. The discrete Agfilament with Si nanocrystalline and complete Ag filament is proposed to be responsible for theperformance IRS and LRS. We supposed that the Ag+ ions prefer to be reduced to Ag atoms nearthe Si nanocrystalline location. Si nanocrystalline between Ag nanoparticles contribute to thecurrent transport at IRS. [ABSTRACT FROM AUTHOR]

To enable atomic-scale observations of model catalysts under conditions approaching those used by the chemical industry, we have developed a second generation, high-pressure, high-temperature scanning tunneling microscope (STM): the ReactorSTM. It consists of a compact STM scanner, of which the tip extends into a 0.5 ml reactor flow-cell, that is housed in a ultra-high vacuum (UHV) system. The STM can be operated from UHV to 6 bars and from room temperature up to 600 K. A gas mixing and analysis system optimized for fast response times allows us to directly correlate the surface structure observed by STM with reactivity measurements from a mass spectrometer. The in situ STM experiments can be combined with ex situ UHV sample preparation and analysis techniques, including ion bombardment, thin film deposition, low-energy electron diffraction and x-ray photoelectron spectroscopy. The performance of the instrument is demonstrated by atomically resolved images of Au(111) and atom-row resolution on Pt(110), both under high-pressure and high-temperature conditions. [ABSTRACT FROM AUTHOR]

High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles. Velocity resolution approaches 0.1 m/s by using the local constant velocity approximation. [ABSTRACT FROM AUTHOR]

The effects of MoO3 molecular doping in poly(3,4-ethylenedioxythiophene):poly(stylenesulfonate) (PEDOT:PSS) on the chemical structure and, in turn, on the carrier collection efficiency of c-Si/PEDOT:PSS heterojunction solar cells are demonstrated. Scanning electron microscopy revealed that the hydrophilic PSS polymer chain was intercalated into the interlayer van der Waals gap of MoO3 flake sheets, which modified the chemical structure of PEDOT:PSS. MoO3 exhibited intense photoluminescence in the 350-550 nm region, which enhanced the carrier collection efficiency of c-Si/PEDOT:PSS heterojunction solar cells with no significant changes. These findings suggest that the intense photoluminescence of MoO3 and its light wavelength conversion contribute to the increased carrier collection efficiency. [ABSTRACT FROM AUTHOR]

In this work, we present a comprehensive experimental study of charge loss mechanisms in a dual-layer metal nanocrystal (DL-MNC) embedded high-κ/SiO2 gate stack. Kelvin force microscopy characterization reveals that the internal-electric-field assisted tunneling could be a dominant charge loss mechanism in DL devices that mainly depends on the charge distribution in two MNC-layers and inter-layer dielectric (ILD) thickness between the two layers of nanocrystals. Our findings suggest that an optimized DL-MNCs embedded memory cell could be achieved by defining the ILD thickness larger than the average MNC-spacing for enhancement of retention ability in MNC embedded gate stacks. It implies the possibility of reducing MNC spacing in DL structure of scaled memory devices by controlling the thickness of ILD. [ABSTRACT FROM AUTHOR]

The N = 2 supercomformal transformations are employed to study supersymmetric integrable systems. It is proved that two known N = 2 supersymmetric Harry Dym equations are transformed into two N = 2 supersymmetric modified Korteweg-de Vries equations, thus are connected with two N = 2 supersymmetric Korteweg-de Vries equations. [ABSTRACT FROM AUTHOR]

Darboux transformation is constructed for a third-order spectral problem. By proper reduction, a Darboux transformation for a long-short wave model is obtained. Furthermore, a closed multi-soliton solution formula is found for this equation. [ABSTRACT FROM AUTHOR]

The supersymmetric analog of the reciprocal transformation is introduced. This is used to establish a transformation between one of the supersymmetric Harry Dym equations and the supersymmetric modified Korteweg-de Vries equation. The reciprocal transformation, as a Bäcklund-type transformation between these two equations, is adopted to construct a recursion operator for the supersymmetric Harry Dym equation. By proper factorization of the recursion operator, a bi-Hamiltonian structure is found for the supersymmetric Harry Dym equation. Furthermore, a supersymmetric Kawamoto equation is proposed and is associated with the supersymmetric Sawada-Kotera equation. The recursion operator and odd bi-Hamiltonian structure of the supersymmetric Kawamoto equation are also constructed. [ABSTRACT FROM AUTHOR]

Due to the gradual depletion and excessive consumption of fossil fuels and the resulting environmental problems, increasing attention has been paid to the utilization of the renewable energy sources such as solar energy, etc. The development and performance investigation of a photovoltaic-powered refrigerator is presented in the paper. The field performance test results show that the refrigerator can work well in Shanghai area and the lowest temperature in the freezer can reach near -15 °C and the power consumption is also reasonable. Furthermore, the energy flow of the system and applicability of it to different climatic regions have been analyzed and discussed. It can be concluded that the performance of the refrigerator is very stable and it can serve for perishable food storage, vaccine, and drug depositing at low temperatures in the remote area and it can even be used as the electrical appliance in “zero-energy” building. [ABSTRACT FROM AUTHOR]

The mean value of a quantity in an equally weighted wave packet was recently found in the classical limit to be the Feje´r average of partial sums of Fourier series expansion of the classical quantity, and the number of stationary states in it is equal to that of partial sums. The incompleteness of the Feje´r average in representing a classical quantity enables us to define a classical uncertainty relation which turns out to be the counterpart of the quantum one. In this paper, two typical quantum systems, a harmonic oscillator and a particle in an infinite square well, are used to illustrate the above-mentioned points. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A correction to the article "Optical and Carrier Transport Properties of Graphene Oxide based crystalline-Si/organic Schottky Junction Solar Cells" that was published in the 2013 issue is presented.

The perfectly matched layer (PML) for elastic waves in cylindrical and spherical coordinates is developed using an improved scheme of complex coordinates. As is known for electromagnetic waves, Berenger's original PML scheme does not apply to cylindrical and spherical coordinates. The straightforward extension of the complex coordinates for elastic waves to cylindrical and spherical coordinates requires extra unknowns for time-domain solutions, wasting computer memory and computation time. The main idea of the improved scheme in this work is the use of integrated complex variables. It is shown that for three-dimensional cylindrical and spherical coordinates, this improved PML scheme requires no more unknowns than in Cartesian coordinates. The number of unknowns can be further reduced through the use of symmetry in the partial differential equations. The PML scheme allows an arbitrary inhomogeneity in the medium, and is suitable for numerical solutions of wave equations by finite-difference, finite-element, and pseudospectral methods for elastic waves in inhomogeneous media with cylindrical and spherical structures. Finite-difference time-domain (FDTD) results are shown to demonstrate the efficacy of the PML absorbing boundary condition. © 1999 Acoustical Society of America. [ABSTRACT FROM AUTHOR]

Physically interesting exact solutions are constructed for a large class of nonlinear nonintegrable evolution equations. These solutions describe the interaction of traveling waves. They exhibit rich phenomenology including breaking of solitary waves. Generalized conditional symmetries and bilinearity are used to derive these exact results. [ABSTRACT FROM AUTHOR]