Purpose Si-based micro electro mechanical systems (MEMS) magnetometer does not require specialized magnetic materials avoiding magnetic hysteresis, ease in fabrication and low power consumption. It can be fabricated using the same processes used for gyroscope and accelerometer fabrication. The paper reports the dicing mechanism for the released MEMS xylophone magnetic sensor fabricated using wafer

Purpose The aims of this paper is to study the effects of the V/III ratio of indium gallium nitride (InGaN) quantum wells (QWs) on the structural, optical and electrical properties of near-ultraviolet light-emitting diode (NUV-LED). Design/methodology/approach InGaN-based NUV-LED is successfully grown on the c-plane patterned sapphire substrate at atmospheric pressure using metal organic chemical vapor

The structural electronic and magnetic properties of the double perovskite Ca2CrNbO6 in the cubic structure are investigated using the empirical full-potential linearized augmented plane wave (FP-LAPW) method within the framework of the spin-polarized density functional theory (DFT). These properties are calculated using the Generalized Gradient Approximation (GGA), GGA+U and modified Becke–Johnson

In this work, Monte Carlo simulations have been performed to investigate the magnetic properties and thermal behavior of different Husimi-like structures: triangular, square and pentagonal. In fact, the Blume-Capel model has been adopted to study such Husimi lattices in the framework of the Ising model spin-1. Furthermore, we have examined the computed blocking temperatures. Also, the behavior of each

In this work, we investigate the scattering phenomena at the inhomogeneous boundary of a magnetic interface in two-dimensional (2D)-triangular ferromagnetic waveguide. We especially examine two ferromagnetic interfaces, named heavy and superheavy solitons in 2D-triangular lattices. The system is supported on a nonmagnetic substrate. Therefore, each spin site in the lattice can be considered free from

Thermoelectric properties of superlattice magnetic tunnel junctions (SL-MTJs) comprising of MgO barriers, ZnO quantum wells and CoFeB contacts are investigated in the linear and nonlinear response regime. The transmission function is calculated by the nonequilibrium Green’s function (NEGF) formalism. The anti-reflective (AR) regions idea in SL-MTJs leads to an enhancement in power factor as well as

In this paper, we present an ab initio study, based on the density functional theory (DFT) approach and GGA-PBE approximation, of the structural, electronic and magnetic properties of new quaternary Heusler compounds LiX′NO (X′=Ba, Ca and Sr). We searched the structural stability of these quaternary Heusler among three different atomic arrangements (type-1, type-2 and type-3) by calculating of the

The structural, electronic, elastic and magnetic properties of CoCrScIn were investigated using first principle calculations with applying the full-potential linearized augmented plane waves (FP-LAPW) method, based totally on the density functional theory (DFT). After evaluating the results, the calculated structural parameters reveal that CoCrScIn compound is stable in its ferrimagnetic configuration

A novel lead zinc titanate tungsten oxide (PbZn1∕3Ti1∕3W1∕3O3) single perovskite was synthesized employing a cost-effective solid-state reaction technique. A phase transition occurs from tetragonal (P4mm) to monoclinic (C2/m) after substituting zinc (Zn) and tungsten (W) into the B-site of the pure lead titanate. The average crystallite size and micro-lattice strain are 66.2nm and 0.159%, respectively

Purpose The purpose of this study is to investigate the influence of AlN nucleation thickness in reducing the threading dislocations density in AlN layer grown on sapphire substrate. Design/methodology/approach In this work, the effect of the nucleation thickness at 5 nm, 10 nm and 20 nm on reducing the dislocation density in the overgrown AlN layer by metal organic chemical vapor deposition was discussed

Purpose The purpose of this paper is to investigate the effect of growth temperature on the evolution of indium incorporation and the growth process of InGaN/GaN heterostructures. Design/methodology/approach To examine this effect, the InGaN/GaN heterostructures were grown using Taiyo Nippon Sanso Corporation metal-organic chemical vapor deposition (MOCVD) SR4000-HT system. The InGaN/GaN heterostructures

Purpose This paper aims to report the influence of sputtering plasma deposition time on the structural and mechanical properties of the a-axis oriented aluminium nitride (AlN) thin films. Design/methodology/approach The AlN films were prepared using RF magnetron sputtering plasma on a silicon substrate without any external heating with various deposition times. The films were characterized using X-ray

Purpose The purpose of this paper is to present the performance of an 8-bit hybrid DAC which is suitable for wireless application or part of a built-in test block for ADC. The hybrid architecture used is the combination of thermometer coding and binary-weighted resistor architectures. Design/methodology/approach The conventional DAC topology performance tends to degrade at high-resolution applications

Major loss factors for photo-generated electrons due to the presence of surface defects in titanium dioxide (TiO2) were controlled by RF-sputtered tungsten trioxide (WO3) passivation. X-ray photoelectron spectroscopy assured the coating of WO3 on the TiO2 nanoparticle layer by showing Ti 2p, W 4f and O 1s characteristic peaks and were further confirmed by X-ray diffraction studies. The coating of WO3

A compact pixel for single-photon detection in the analog domain is presented. The pixel integrates a single-photon avalanche diode (SPAD), a passive quenching & active recharging circuit (PQARC), and an analog counter for fast and accurate sensing and counting of photons. Fabricated in a standard 0.18 m CMOS technology, the simulated and experimental results reveal that the dead time of the PQARC

An improved small-signal equivalent circuit of HBT concerning the AC current crowding effect is proposed in this paper. AC current crowding effect is modeled as a parallel RC circuit composed of C bi and R bi, with distributed base-collector junction capacitance also taken into account. The intrinsic portion is taken as a whole and extracted directly from the measured S-parameters in the whole frequency

Herein, high-quality n-ZnO film layer on c-sapphire and well-crystallized tetragonal p-BiOCl nanoflakes on Cu foil are prepared, respectively. According to the absorption spectra, the bandgaps of n-ZnO and p-BiOCl are confirmed as ~3.3 and ~3.5 eV, respectively. Subsequently, a p-BiOCl/n-ZnO heterostructural photodetector is constructed after a facile mechanical bonding and post annealing process.

AlN single crystal grown by physical vapor transport (PVT) using homogeneous seed is considered as the most promising approach to obtain high-quality AlN boule. In this work, the morphology of AlN single crystals grown under different modes (3D islands and single spiral center) were investigated. It is proved that, within an optimized thermal distribution chamber system, the surface temperature of

In this paper, we discuss low-temperature hopping-conductivity behavior in the insulating phase, in the absence of a magnetic field. We conduct a theoretical study of the crossover from hopping to activated transport in a GaAs two-dimensional hole system at low temperatures, finding that a crossover takes place from the Efros-Shklovskii variable-range hopping (VRH) regime to an activated regime in

Gallium nitride (GaN)-based high-electron mobility transistors (HEMTs) are widely used in high power and high frequency application fields, due to the outstanding physical and chemical properties of the GaN material. However, GaN HEMTs suffer from degradations and even failures during practical applications, making physical analyses of post-failure devices extremely significant for reliability improvements

Purpose The purpose of this study is to address the issue of technology equipment formerly dedicated to the process of 4- and even 5-inch photovoltaic cells and whose use has become critical with the evolution of silicon wafer size standards (M2–M10). Fortunately, the recent concept of 6'' half-cut cell with its many advantages appears promising insofar as it offers the possibility of further extend

We propose a low-speed photonic sampling for independent high-frequency characterization of a Mach–Zehnder modulator (MZM) and a photodetector (PD) in an optical link. A low-speed mode-locked laser diode (MLLD) provides an ultra-wideband optical stimulus with scalable frequency range, working as the photonic sampling source of the link. The uneven spectrum lines of the MLLD are firstly characterized

A nonlinear integrated optical platform that allows the fabrication of waveguide circuits with different material composition, and at small dimensions, offers advantages in terms of field enhancement and increased interaction length, thereby facilitating the observation of nonlinear optics effects at a much lower power level. To enhance the nonlinearity of the conventional waveguide structure, in this

We report a low-cost manufacturing approach for fabricating monolithic multi-wavelength sources for dense wavelength division multiplexing (DWDM) systems that offers high yield and eliminates crystal regrowth and selective area epitaxy steps that are essential in traditional fabrication methods. The source integrates an array of distributed feedback (DFB) lasers with a passive coupler and semiconductor

Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing. Waveguide-based external cavity narrow linewidth semiconductor lasers (WEC-NLSLs) have become a competitive and attractive candidate for many coherent applications due to their small size, volume, low energy consumption, low cost and the ability to integrate with other optical components

Efficient light generation and amplification has long been missing on the silicon platform due to its well-known indirect bandgap nature. Driven by the size, weight, power and cost (SWaP-C) requirements, the desire to fully realize integrated silicon electronic and photonic integrated circuits has greatly pushed the effort of realizing high performance on-chip lasers and amplifiers moving forward.

It is very attractive to apply a directly modulated laser (DML)-based intensity-modulation and direct-detection (IM/DD) system in future data centers and 5G fronthaul networks due to the advantages of low cost, low system complexity, and high energy efficiency, which perfectly match the application scenarios of the data centers and 5G fronthaul networks, in which a large number of high-speed optical

We review recent work on narrowband orthogonally polarized optical RF single sideband generators as well as dual-channel equalization, both based on high-Q integrated ring resonators. The devices operate in the optical telecommunications C-band and enable RF operation over a range of either fixed or thermally tuneable frequencies. They operate via TE/TM mode birefringence in the resonator. We achieve

Lithium niobate on insulator (LNOI) is rising as one of the most promising platforms for integrated photonics due to the high-index-contrast and excellent material properties of lithium niobate, such as wideband transparency from visible to mid-infrared, large electro-optic, piezoelectric, and second-order harmonic coefficients. The fast-developing micro- and nano-structuring techniques on LNOI have

Hybrid integration of III–V and ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits (PICs). Bonding and transfer printing have been the popular approaches for integration of III–V gain media with silicon PICs. Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths, higher linearity, lower

We review recent work on broadband RF channelizers based on integrated optical frequency Kerr micro-combs combined with passive micro-ring resonator filters, with microcombs having channel spacings of 200 and 49 GHz. This approach to realizing RF channelizers offers reduced complexity, size, and potential cost for a wide range of applications to microwave signal detection.

Optical frequency combs have emerged as an important tool enabling diverse applications from test-and-measurement, including spectroscopy, metrology, precision distance measurement, sensing, as well as optical and microwave waveform synthesis, signal processing, and communications. Several techniques exist to generate optical frequency combs, such as mode-locked lasers, Kerr micro-resonators, and electro-optic

An Erratum to this paper has been published: https://doi.org/10.1134/S1063782621030192

Abstract An analysis of the I–V characteristics makes it possible to determine the mechanisms of conduction corresponding to different states of the flow channels upon resistive switching in porphyrazine films. A variation in the temperature, the structure of the dielectric matrix, and the type of majority charge carriers makes it possible to estimate the applicability of the model of conducting filaments

Abstract The features of the electrochemical deposition of metal coatings on p-Si are presented, and the properties of the grown metal layers are measured. The dependence of the depleted-region thickness and the internal voltage drop in it on the electrolyte composition and deposited metal type is studied. The effect of the current density and electrolyte composition on the precipitate properties is

Abstract The impact of the shape of indium-antimonide quantum dots on some important electrical parameters is investigated by the analysis of their optical spectra, transmission electron microscopy, scanning tunneling microscopy, particle size measurements, and scanning electron microscopy. It is shown that the real shape (spherical and cubic models) of quantum dots with the same characteristic size

Abstract Improving material quality is essential for obtaining a high-power device. Surface trapping effects have been present in all HEMT devices, and have significantly impacted the problem of drain-current collapse. In this paper, performance of intentionally non-doped AlGaN|GaN|Si (HEMTs) before and after passivation with SiO2|SiN is investigated. Capacitance-voltage at various temperatures (C–V–T)

Abstract Due to the lack of work in structures containing thallium (Tl), this work is devoted to study of Ga8Tl2N quantum-dot photodetectors. Parameters are specified first. This structure is shown to have low absorption. Enough quantum efficiency is obtained. This detector works at 360–460 nm and peaked at 410 nm, which can be used in optical coherence tomography applications.

Abstract The effects of the high-temperature (T = 1880°C) diffusion of beryllium ions and of electron irradiation on the optical properties of single-crystal aluminum nitride is studied. It is shown that the introduction of Be into AlN results in a change in the spectral characteristics of Raman scattering and infrared absorption. The analysis of Raman spectra and infrared adsorption spectra in crystals

Abstract The propagation of solitary acoustic pulses in magnetized quantum electron–hole plasmas of semiconductors has been studied. The effects of an external magnetic field and quantum terms, including the electrons and holes quantum recoil effects, exchange-correlation force, and the degenerate pressure of charge carriers are considered. Starting from quantum hydrodynamic equations, by using the

Abstract The effect of ambient humidity on the electrical conductivity of α-Ga2O3 and α-Ga2O3/ε-Ga2O3 is investigated. Polymorphic epitaxial Ga2O3 layers are deposited by the method of chloride vapor-phase epitaxy on sapphire substrates. The contacts are made of Pt and Pt/Ti. It is discovered that the I–V characteristics of the Pt/α-Ga2O3/Pt and Pt/Ti/α-Ga2O3/ε-Ga2O3/Ti/Pt structures have a high sensitivity

Abstract High-quality gallium nitride etching is highly desirable in electronic device fabrications. For the GaN base devices, the electronic properties largely depended on the etching induced surface damages. To overcome this, a controllable GaN etching method was developed using inductively coupled plasma reactive ion etching (ICP-RIE) by controlling radio frequency (RF) power, and DC bias. The etching

Abstract The anisotropy of the conductivity and the shape of the I–V characteristics for a two-dimensional quantum superlattice with the nonharmonic electron dispersion law are investigated for different directions of the current and field applied to the structure relative to the superlattice axes. The anisotropy of the characteristics and the conditions for the occurrence of multivalue I–V characteristics

Abstract Textured ZnO films obtained on amorphous substrates using the ion-beam sputtering method are studied. X-ray diffraction and atomic-force microscopy methods show that the resulting films have a polycrystalline structure immediately after deposition. It is established that further annealing of the samples in the temperature range from 200°C to 500°C results in recrystallization, which leads

Abstract Copper zinc tin sulphide (CZTS) thin films have been deposited on glass substrate at 323 ± 5 K using sequential ionic layer adsorption reaction (SILAR). The number of SILAR cycles required for optimum crystalline quality CZTS thin films was optimized. The as-deposited CZTS thin films showed kesterite crystalline structure with preferential orientation along (103) plane. Structural, optical

Abstract A study of the electroluminescence of asymmetric InAs/InAs1 – ySby/InAsSbP light-emitting diode heterostructures with a molar fraction of InSb in the ternary solid solution in the active region y = 0.15 and y = 0.16 in the temperature range 4.2–300 K is reported. It is found on the basis of experimental data that a staggered type-II heterojunction is formed at the InAs1 – ySby/InAs0.41Sb0

Abstract The influence of the topology of electrodes on the electrical and photoelectric characteristics of metal–semiconductor–metal structures is studied. Gallium-oxide films are produced by the radio-frequency magnetron-assisted sputtering of a Ga2O3 target onto (0001)-oriented sapphire substrates. Two types of electrodes are formed on the surface of the oxide films. The first type corresponded

Abstract In the present paper, a Pb-free and eco-friendly perovskite solar cell (PSC) with a new structure of glass|TCO|TiO2|CZTSe1 – xSx|CH3NH3SnI3|back contact has been modeled and simulated by SCAPS-1D package. To verify the simulation process, an experimental report on Pb-free PSC was simulated initially. Then, the costly Spiro-OMeTAD layer as the common hole-transport material (HTM) was eliminated

Abstract Edge-emitting lasers with active regions based on novel InGaAs/GaAs quantum heterostructures of transitional dimensionality, i.e., quantum well-dots, which are intermediate in properties between quantum wells and quantum dots, are studied. It is shown that the rate of the lasing-wavelength blue shift decreases with increasing number of quantum well-dot layers in the active region and with

Abstract The diffusion of indium atoms in silicon-dioxide films previously implanted with arsenic ions with different energies is studied in relation to the temperature of postimplantation annealing. It is established that the diffusion properties of indium depend on the presence of arsenic atoms in the film and their energy. An increase in the As content in the region of the average projective range

In this study, we have presented a systematic theoretical study about the electronic, magnetic and structural properties of the full-Heusler compound Fe2CuSi based on first principles calculations. The L21-type structure with ferromagnetic configuration is determined to be the ground state. The calculated electronic band structures show metallic behavior for both spin direction and the obtained total

Magnetic tunnel junction with perpendicular magnetic anisotropy (p-MTJ) is the core component in spintronics-based memory, logic and sense devices, the synthetic anti-ferromagnetic (SAF) has been used to fix the reference layer and cancel the stray field in free layer and few works report the SAF-based reliability analysis of p-MTJ nanopillars. Here, we developed a complete set of method for single

This research work studies the structural, electronic and magnetic properties of Ge1_xTixTe (for x=0.25, 0.50, 0.75, 1) compounds in rock-salt structure based on first-principles spin-polarized density functional theory. As it is implemented in WIEN2k code, the full-potential augmented plane-wave method was used in the investigation. To evaluate the structural properties of compounds, the exchange-correlation

In high-Tc superconductors, electrons form pairs and electric transport becomes dissipation-less at low temperatures. The iron-based superconductors (FeSCs) have the highest superconducting (SC) transition temperature next to copper oxides. The gap structure and pairing mechanism for FeSCs are hotly discussed as a central issue since their discovery. A model Hamiltonian for the superconductivity in

The spin and pseudo-spin symmetries are analytically investigated by solving the three-dimensional Dirac equation for the Kratzer potential plus a ring-shaped potential. Relativistic Schrödinger-like wave equations coupled in energy are derived from Dirac equation. The energy eigenvalues and eigenfunctions are calculated by solving the coupled relativistic radial, and angular wave equations in the

The theoretical aspects of research on the role of Jahn–Teller (JT) interactions in quasi-two-dimensional iron-based high-Tc superconductors are analyzed. A model Hamiltonian for the JT distortion in iron-based superconductors is proposed by a tight-binding two-orbital model. We have proposed here a s±-wave pairing symmetry of the form coskx×cosky in the model in mean-field approximation. The model

The aim purpose of this study is to investigate the structural, elastic, magnetic, electronic properties and half-metallic stability under pressure of ScNiCrZ (Z=Al, Ga and In) quaternary Heusler alloys using full-potential linear muffin-tin orbital (FP-LMTO) method within the gradient generalized approximation (GGA) for exchange, and correlation potential. In order to evaluate the stability of our

In this paper, we have used the Monte Carlo simulations (MCSs) to investigate the magnetic properties of the brownmillerite KBiFe2O5 (KBFO) compound. The different exchange coupling interactions J1, J2 and J3 between different irons Fe atom have been outlined including the angles between Fe1-O-Fe2. The double exchange interaction is caused by the existence of the oxygen atoms. In a first step, we present

In this work, we have studied the structural, optoelectronic, elastic and thermoelectric properties for halides doubles perovskites compounds K2GeSiX6 (X=F, Cl, Br and I). Based on the linearized augmented plane wave method with full potential (FP-LAPW) method, the previous properties are treated within GGA-PBE and the modified Beck–Johnson correction (mBJ-GGA) approximations. The results show that

The full-potential linearized augmented plane waves (FP-LAPW) method, within the density functional theory (DFT), has been used to investigate the structural and elastic properties of KRbAs, KNaAs and NaRbAs. The obtained results, utilizing the generalized gradient approximation (GGA), revealed that all compounds prefer their type-I structure ferromagnetic (FM) phase. However, only two among them,