The magnetic properties of anisotropic 3D Ising model on a cubic lattice are studied by Monte Carlo simulation. In particular, we have considered an extended 3D Ising model with spatially uniaxial anisotropic bond randomness on the simple cubic lattice parameterized by exchange interaction parameter J, anisotropy parameter a and external longitudinal magnetic field h. The obtained numerical data clearly

We report on the effect of Carbon insertion on the microstructure and magnetic properties of nanocrystalline Pr2Co7Cx(x≤1). The Pr2Co7Cx were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and physical property measurement system (PPMS9) Quantum Design. Mean field theory was utilized to depict the temperature dependence of magnetization and deduce the exchange interactions

A model for lateral-type refracting-facet spin-photodiodes based on ferromagnetic metal-insulator-semiconductor (FM-I-S) junctions is described. The model utilizes spin and charge drift-diffusion equations and spin-dependent tunneling equations which are simultaneously solved numerically in order to obtain a self-consistent solution. The model is used to analyze and optimize the refracting-facet spin-photodiode

We review the formulation of gauge fields in terms of the frame of reference as well as the space in which the frame is defined. We highlighted some recent applications of gauge physics in the momentum space — in the modern fields of the spin Hall effect, the magnon Hall, the optical Magnus and the graphene valley Hall. General procedures of gauge transformation which lead to the construction of the

This work presents ab initio study of the structural, electronic, magnetic and mechanical properties of Fe2NiAl1−xGax Heusler compounds with variable concentrations (x=0, x=0.25, x=0.50, x=0.75 and x=1) of Ga. Calculations have performed using the full-potential linearized augmented plane waves (FP-LAPW) method within generalized gradient approximation Perdew–Burke–Ernzerhof (GGA-PBE) formalism in

In this study, we report the electronic structure properties of SmFe2 and HoCo2 binary Laves phase compounds using the density functional theory (DFT) method. We treated the exchange correlation potential with generalized gradient approximation (GGA); in addition, GGA+U (U: Hubbard correction) calculations were applied to describe the correlation effects. At the equilibrium state, the lattice parameter

Lead magnesium tungsten titanate PbMg1∕3 Ti1∕3W1∕3O3 was prepared by adopting a high-temperature solid-state reaction method. The sample has tetragonal crystal structure having average crystallite size 45.1325nm calculated using Scherer’s relation and the average grain size is about 40nm from Scanning Electron Microscope (SEM) measurement. Measurements of dielectric permittivity (εr) and loss (tanδ)

The first-principles approach based on density functional theory (DFT) and the full-potential linearized augmented plane-wave method were employed to investigate the structural, elastic, electronic and magnetic properties of NaXNO (X=Ca, Sr and Ba) quaternary half-Heusler alloys. The generalized gradient approximation (GGA) as parameterized by Perdew, Burke and Ernzerhof (PBE) and the modified Becke–Johnson

Double perovskites are usually strongly correlated electronic systems that offer many multifunctional properties and are most commonly formed in the monoclinic crystal phase. In this study, we used a first-principles DFT approach in studying the optical and magnetic aspects of Ba2MMoO6 (M=Mn, Fe) double perovskite structures in a new monoclinic phase in both their pure and oxygen-deficient form and

Purpose This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation

Purpose The purpose of this study is to design and fabricate a simple passive sensor circuitry embedded into a printed circuit board (PCB) and then to examine its properties. Design/methodology/approach A passive sensor transponder integrated circuit (IC) working in the high frequency (HF) 13.56 MHz frequency band was selected for this study. A loop antenna was designed to make the reported sensor

We report on our results obtained on the physical properties of BxInyGa1−x−yN quaternary alloys in the zinc-blende phase that are thoroughly considered by the linearized augmented plane wave method, with a full potential within density functional theory, for different concentrations x and y as employed in the Wien2k code. We calculated the structural properties, including lattice constant a0 and the

Organic zinc-ion batteries (OZIBs) are emerging rechargeable energy storage devices and have attracted increasing attention as one of the promising alternatives of lithium-ion batteries, benefiting from the Zn metal (low cost, safety and small ionic size) and organic electrodes (flexibility, green and designable molecular structure). Organic electrodes have exhibited fine electrochemical performance

Hydrogen can be sustainably produced through photoelectrochemical (PEC) water splitting. The process of PEC water splitting is composed of two vital half-reactions: water oxidation to O 2 on photoanode, and proton reduction to H 2 on photocathode. Both in thermodynamics and kinetics, the oxidation of water on photoanode is much more challenging, because the formation of O 2 involves the four-holes

Photocatalytic hydrogen evolution is one of the most promising ways to solve environmental problems and produce a sustainable energy source. To date, different types of photocatalysts have been developed and widely used in photocatalytic hydrogen evolution. Recently, multinary copper chalcogenides have attracted much attention and exhibited potential applications in photocatalytic hydrogen evolution

Solar water splitting is a promising strategy for the sustainable production of renewable hydrogen and solving the world’s crisis of energy and environment. The third-generation direct bandgap semiconductor of zinc oxide (ZnO) with properties of environmental friendliness and high efficiency for various photocatalytic reactions, is a suitable material for photoanodes because of its appropriate band

Metal-organic frameworks (MOFs) with orderly porous structure, large surface area, high electrochemical response and chemical tunability have been widely studied for energy conversion and storage. However, most reported MOFs still suffer from poor stability, insufficient conductivity, and low utilization of active sites. One strategy to circumvent these issues is to optimize MOFs via designing composites

As a promising photocatalysis material, TiO 2 has long been studied by experimental and theoretical methods. The external strain could affect the catalytic reactivity of TiO 2 significantly due to the difference in surface elastic properties of different surface structures with different surface adsorption or defects. This article reviews our recent work by using density function theory calculations

The exploitation of renewable energy as well as the elimination of the harmful impact of excessive carbon emission are worldwide concerns for sustainable development of the ecological environment on earth. To address that, the technologies regarding energy conversion systems, such as water splitting and electroreduction of carbon dioxide, have attracted significant attention for a few decades. Yet

Lithium–sulfur (Li–S) battery with a new configuration is demonstrated by inserting a flexible nitrogen-doping carbon nanofiber (N-CNFs) interlayer between the sulfur cathode and the separator. The N-CNFs film with high surface roughness and surface area is fabricated by electrospinning and a subsequent calcination process. The N-CNFs film interlayer not only effectively traps the shuttling migration

Due to the quantum size effect and other unique photoelectric properties, quantum dots (QDs) have attracted tremendous interest in nanoscience, leading a lot of milestone works. Meantime, the scope and scientific connotation of QDs are constantly expanding, which demonstrated amazing development vitality. Besides the well-developed Cd-containing II–VI semiconductors, QDs of environmentally friendly

As an emerging organic semiconductor, perylene diimide (PDI) self-assembly has attracted tremendous attention in the aspects of solar cells, sensors, fluorescence probes and n-transistors, etc. In term of photocatalysis, various photocatalysts based on PDI self-assembly exhibit some unique properties, such as intrinsic Π-Π stacking structure, fast internal charge transfer, band-like electronic structure

Purpose The purpose of this paper is to demonstrate the acceptable performance by using the limited input range towards lower open-loop DC gain operational amplifier (op-amp) of an 8-bit pipelined analog-to-digital converter (ADC) for mobile communication application. Design/methodology/approach An op-amp with folded cascode configuration is designed to provide the maximum open-loop DC gain without

Abstract The study concerns the issue of how the morphological characteristics and optical properties of morphologically branched InGaN nanostructures grown on the Si(111) surface by molecular-beam epitaxy depend on the substrate temperature. It is shown that, as the substrate temperature is elevated, the height of InGaN nanocolumns formed at the initial stage of growth increases. In addition, an increase

Abstract It is known that diamond-like carbon layers consist of carbon components with sp2 (graphite) and sp3 (diamond) hybridizations of electron orbitals. The quantitative ratio between sp2 and sp3 components has a profound effect on the structural, morphological, optical, electrical, and mechanical properties of the films. In this study, the possibility of controlling the fractions of sp2- and sp3-hybridized

Abstract The relaxation rates of arsenic donor states in germanium upon interaction with acoustic phonons are analyzed depending on uniaxial crystal compression deformation along [110] direction at low temperatures (<10 K). It is shown that the formation of the inverse population of donor levels, which depends on the crystal-deformation magnitude, occurs under optical excitation, which gives us grounds

Abstract Cu2ZnSnS4 is suitable for high-performance thin-film solar cell because of its high absorbance coefficient, presence of non-toxic elements, excellent optoelectronic properties, and a near-perfect direct band gap. The effect of thermal annealing time (1–4 h) on the optical, morphological, and structural properties of Cu2ZnSnS4 coated through a simple solution processable method has been studied

Abstract The features of the surface shape of GaAs epitaxial layers grown on grooves several micrometers wide with vertical walls and an aspect ratio close to unity are investigated. The grooves are formed on the surface of a GaAs wafer in a plasma-chemical etching installation and overgrown by organometallic vapor-phase epitaxy under reduced pressure in a reactor.

Abstract Data on the synthesis of structures for a quantum cascade terahertz laser in the AlGaAs/GaAs material system on GaAs substrates using the molecular-beam-epitaxy method and their characterization are presented. The specific features necessary for the implementation of such structures are considered. It is shown that, for this configuration, almost single-mode lasing is observed at a frequency

Abstract The fabrication process of ohmic contacts to a diamond-like carbon (DLC) layer is described with the sequential deposition of a Au/Mo/Ti metallic layer onto it. The contacts have good mechanical and adhesion properties. Their specific contact resistance is varied from 1.4 × 10–4 to 6.4 × 10–5 Ω cm2 depending on the DLC layer thickness. The temperature dependence of the layer film resistance

Abstract It is shown for the first time that Co subnanometer coatings deposited by molecular-beam epitaxy on the (0001) surface of the topological insulator BiSbTeSe2 at a temperature of 330°C open an energy gap in the spectrum of topological surface states in the region of the Dirac point with a shift of the Dirac-point position caused by the preliminary deposition of an adsorbate at room temperature

Abstract The photoluminescence spectra of waveguide AlSb/InAs/GaInSb/InAs/AlSb quantum-well heterostructures designed for the generation of radiation at interband transitions in the mid-infrared region have been studied. The experimentally detected spectral lines are correlated with calculations of the band structure.

Abstract The nonlinearity of the gate–drain current–voltage characteristics in classical Schottky transistors and two-dimensional electron gas field-effect transistors based on AlGaAs/InGaAs/GaAs and InGaAs/GaAs compounds is analyzed. The carrier velocity-overshoot effect in the transistor channel is analyzed for various doping profiles of the structures under study.

Abstract The results of experiments aimed at fabricating and studying the properties of photodetector structures based on single-layer graphene produced by chemical vapor deposition are presented. The configuration of a Ta2O5 vertical microcavity with a resonance wavelength of about 850 nm and a lower dielectric SiO2/Ta2O5 distributed Bragg reflector is taken as the base structure. The conditions for

Abstract The photoresponse is investigated in the frequency range of 0.15–15 THz in HgCdTe epitaxial layers with a cadmium concentration from 15.2 to 19.2% grown by molecular-beam epitaxy. It is shown that narrow-gap and gapless HgCdTe solid solutions can be used as detectors of both terahertz and sub-terahertz radiation with a characteristic response time of 2–4 ns and with a sensitivity approaching

Abstract The rate of the multiphonon relaxation of the 1s(T2) level in Se+ donors in silicon is estimated. The calculation comprises the initial approach to the problem, in which the most simplified form of wave functions is used. To evaluate the transition probability, the Pässler expression known from publications is used [R. Pässler, Czech. J. Phys. B 24, 322 (1974)]. This expression was derived

Abstract The change in the carrier mobility in GaAs structures after irradiation is numerically simulated. For each investigated scattering potential, the model parameters are determined at which the calculation data are consistent with the results of the experiment. It is shown for the first time that the form of the potential of scattering at radiation-induced defects determines the time and space

Abstract We interpret the recent observations of Otsuji’s team (Sendai) on switching from absorption to amplification at a temperature of T = 300 K during the passage of terahertz radiation through hexagonal boron nitride–graphene sandwiches with multiple gates on the surface with an increase in the electric field in graphene. It is shown that these effects are related to dispersion and negative conductivity

Abstract Within the coupled wave method complemented by the quasi-optical approach, the feasibility of diffraction-mode selection over the transverse index in lasers with planar Bragg resonators is studied. Acceptable Fresnel parameters at which the diffraction losses from the Bragg-structure edges provide steady-state single-mode lasing with a narrow angular spectrum are determined. It is shown that

Abstract The behavior of phosphorus donors in bulk single-crystal monoisotopic Si1 – xGex alloys (x = 0.0039–0.05) enriched by zero-spin isotopes 28Si (99.998%) and 72Ge (99.984%) by the electron-spin-resonance method is investigated. The hyperfine structure of the donor-electron spectrum giving information on the density of the donor wave function in the ground state on the 31P nucleus (I = 1/2) as

Abstract In the present work, we have fabricated and characterized in the development of methylammonium lead iodide (CH3NH3PbI3) perovskite-based hole transport layer (HTL)-free photodiode with configuration (FTO|CH3NH3PbI3|PC60BM{[6,6]-phenyl-C60-butyric acid methyl ester}|Al. The one-step spin coating technique has been used for the deposition of the precursor solution including methylammonium iodide

Abstract ZnO thin films were formed on c-plane sapphire and p-GaN substrates by pulsed laser deposition (PLD) and radio frequency (RF) magnetron sputtering techniques. XRD analysis including omega scan depicted the formation of highly textured wurtzite ZnO with c-axis. The texture was primarily introduced by the substrate effects as the planes lying at oblique angles also exhibited six-fold symmetry

Abstract The spin-depolarized electron system in a GaAs quantum well at the filling factor ν = 1 is investigated using the time-resolved Kerr rotation technique. At temperatures above 5 K, a transition from the new spin-correlated state to a state with a low spin stiffness characteristic of a single-particle electron system is observed. A nonlinear contribution to the damping of Larmor oscillations

Purpose This paper aims to perform experimental test on fatigue characteristics of package on package (POP) stacked chip assembly under thermal cycling load. Some suggestions for design to prolong fatigue life of POP stacked chip assembly are provided. Design/methodology/approach The POP stacked chip assembly which contains different package structure mode and chip position was manufactured. The fatigue

Purpose This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid manipulation of blood components such as red blood cells (RBC) and platelets. The purpose of this investigation is to understand FDEP correlation to the variation of dynamic dielectric properties of cells under an applied voltage

Black phosphorous (BP), an excellent two-dimensional (2D) monoelemental layered p-type semiconductor material with high carrier mobility and thickness-dependent tunable direct bandgap structure, has been widely applied in various devices. As the essential building blocks for modern electronic and optoelectronic devices, high quality PN junctions based on semiconductors have attracted widespread attention

Precise spatial control of 2D materials is the key capability of engineering their optical, electronic, and mechanical properties. However, growth of novel 2D Mo 2 C on Cu surface by chemical vapor deposition method was revealed to be seed-induced 2D growth, limiting further synthesis of complex Mo 2 C spatial structures. In this research, we demonstrate the controlled growth of Mo 2 C pyramids with

A large number of two-dimensional (2D) monoelemental materials with huge application potentials have been developed, since graphene was reported as a monoelemental material with unique properties. As cousins of graphene, 2D group-V elemental monolayers have gained tremendous interest due to their electronic properties with significant fundamental bandgap. In this review, we extensively summarize the

Due to the quantum confinement effect, atomically thin two-dimensional (2D) monolayer materials possess distinct characteristics from their corresponding bulk materials, which have received wide attention from science and industry. Among all the 2D materials, elemental 2D materials with the simplest components are most striking. As an emerging group-VIA elemental 2D monolayer material, tellurene exhibits

Two-dimensional (2D) bismuth, bismuthene, is an emerging pnictogen family member that has received increasing research attention in the past few years, which could yield exotic electrical, thermal, and optical properties due to unique band structure. This review provides a holistic view of recent research advances on 2D bismuth material synthesis and device applications in complementary metal oxide

Abstract A study of the processes of the thermal carbonization of silicon monoxide in the presence of nonstoichiometric carbon monofluoride demonstrated that raising the annealing temperature of mixtures of SiO and CFx powders in a quasi-closed volume to 1000°C and higher leads to the formation of whisker-like SiC nanocrystals. It is found that, in parallel with the known crystallization of SiC nanowires

Abstract After the ion implantation of silicon into sapphire followed by high-temperature annealing, silicon and aluminosilicate precipitates are observed in the surface region of sapphire. X-ray measurements with the mapping of reciprocal space show the presence of a compressive stress with a –0.12% strain in the normal direction, and a tensile stress with a 0.2% strain in the R plane in this region

Abstract Processes of Raman scattering of quasi-single-photon pulses in a single-mode optical fiber with pumping are theoretically considered. The peculiarity of the post-pumping scattering is that the pumping creates non-equilibrium molecular vibrations, which significantly increases the probability of Raman scattering in the optical fiber. Non-equilibrium vibrations are expected when the stimulated

Abstract Nanocrystalline phases and GaAlP films are obtained by implanting Al+ ions with E0 = 1 keV at different doses on the surface of a GaP(111) single crystal, and their electronic and crystalline structures are studied. It is shown that the type and the lattice parameters of the three-component nanostructure are in good agreement with those for the substrate. The relationship between the band

Abstract The dependence of the photoconductivity sign on the bias voltage, intensity, and duration of illumination is studied for PbSnTe:In films in the space-charge-limited current regime. The role of traps (including surface ones) with a complex energy spectrum in the effects under observation is discussed.

Abstract The influence of γ radiation on surface defect formation at the Si–SiO2 interface in a p-type-channel metal—oxide-silicon (MOS) transistor in the passive mode is considered. Several surface-defect formation processes are observed. The role of molecular hydrogen in the undergate oxide of the MOS transistor and “hot” electrons forming in the silicon surface region is shown.

Abstract Electron wave functions in the conduction band of zero-gap HgCdTe alloy are calculated in the Coulomb acceptor field. The resonant-state energies are determined.

Abstract The process of the Pd-assisted etching of silicon in a solution containing HF and H2O2 is investigated. It is shown that the morphology of the forming layers is affected by such factors as the etching duration and solution temperature. It is shown that Pd nanoparticles remain on the walls and bottom of the pores in the course of Pd-assisted etching. Such a structure, as is shown in earlier

Abstract A new method for depositing carbon films by the thermal decomposition of carbon tetrachloride (CCl4) in a hydrogen flux in a reactor for metal-organic chemical vapor deposition (MOCVD) at atmospheric pressure is developed. From the results obtained by Raman spectroscopy, it can be conceived that the carbon layers produced by this method are the disordered nanocrystalline graphite. It is shown

Abstract The phonon modes of quantum-cascade heterostructures based on binary and ternary semiconductor compounds are simulated. The dependences of the frequencies of the structure interface phonon modes on the wave vector in the layer plane and on the phase shift in the superlattice period are calculated. It is found that the range of variation in the quantum energy of phonon modes of the GaAs/Al0