GaAs Material Research Articles

A 90SrHfO3-based betavoltaic/beta-photovoltaic dual-effect integrated nuclear battery

In this paper, the secondary conversion idea is used to reduce the self-absorption effect of the radioactive source by combining the radioactive source with the scintillation material, so as to enhance the energy conversion efficiency of the battery. A theoretical model of a dual-effect integrated nuclear battery based on 90SrHfO3 doped with Ce is proposed. The emission photon and electron spectra of the β-luminescent integrated radioactive source 90SrHfO3 have been calculated by GEANT4. The average outgoing electron energy of SrHfO3 was calculated, and the thickness of the energy reducing material was determined. The effect of structural parameters of GaAs materials on the dual-effect integrated nuclear battery was analyzed to obtain the optimal output performance according to theoretical calculation. From the perspective of conversion efficiency, the activity density and thickness of 90SrHfO3 are determined to be 1.6 Ci/cm2 and 53.6 μm. At this time, the thickness of SrHfO3 is 1.28 mm. The total maximum output power density of the optimized dual-effect integrated nuclear battery is 9.31 μ W/cm2, and the energy conversion efficiency is 0.18 %. At this point, the doping concentrations of GaAs are Na = 1.26 × 1017 cm−3 and Nd = 6.31 × 1018 cm−3, and xj is 0.05 μm. Compared with nonintegrated batteries, the output performance is significantly improved.

Optimization of The Influence of Temperature on The Electrical Distribution of Structures with Radial p-n Junction Structures

In recent years, advances in optoelectronics and electronics have prioritized optimizing semiconductor device performance and reducing power consumption by modeling new semiconductor device geometries. One such innovative structure is the radial p-n junction structure. In this work, we present a concept that submicron three-dimensional simulations were conducted on radial p-n junction structures based on GaAs material to investigate the influence of temperature ranging from 250K to 500K with a step of 50K on the electrophysical distribution, such as space charge, electro-potential, and electric field, in radial p-n junction structures, as well as various forward voltages. In particular, we focus on the shell radius within the structure: 0.5 μm and 1 μm for the shell. The modeling results were compared with the results obtained from solving the theoretical Poisson equation in the cylindrical coordinate system.

Real, imaginary and complex branches of Lamb waves in p-type piezoelectric semiconductor GaAs plate: Numerical and experimental investigation

First, we experimentally measure the concentration of holes of the piezoelectric semiconductor (PSC) Gallium arsenide (GaAs) material based on the Hall effect measurement. We then numerically calculate the Lamb wave characteristics in a p-type PSC GaAs plate using this measured value of the concentration of holes (estimated at approximately p0=3.5431×1025m−3). To guarantee the coupling effect that makes the Lamb wave a piezo-active wave, the GaAs crystal is oriented in a specific orientation of (110) plane. Ordinary differential equation (ODE) method is employed to calculate the dispersion curves, 3D view of the mechanical displacements, 3D view of the electric potential and 3D view of the concentrations of holes. Results show that the appearance of the complex branches of the Lamb modes coincides with the vanishing of the imaginary part of the wavevector (Im(k1)) to zero, which is a very remarkable finding that has not been discussed in previous studies. Meanwhile, these complex branches start exactly at the point of Zero-group-velocity (ZGV). Moreover, the present work highlights the hole drift characteristics of PSC GaAs and provides a critical comparative discussion with those published by (Zhu et al., 2018) for the PSC ZnO plate. Accordingly, the “Screening effect” phenomenon that is based on the positive holes in the negative electric potential region is discussed. The present results provide a theoretical and fundamental guidance on the development of smart devices based on the PSC GaAs material.

Recombination lifetimes and mechanisms of In0.75Ga0.25As and In0.53Ga0.47As as a function of doping density

The minority carrier lifetimes in InGaAs ternary alloys are investigated both experimentally and theoretically. Two groups of InGaAs/InP photodetector samples are designed for experiments, one with In0.75Ga0.25As and the other with In0.53Ga0.47As as the absorption layers. The lifetimes are obtained to be about 100–200 ns in In0.75Ga0.25As and 600 ns-1 µs in In0.53Ga0.47As by microwave photoconductivity decay technique. The calculated lifetimes are also found to be consistent with the experimental ones. Besides, for both InGaAs materials, the Shockley-Read-Hall (SRH), radiative and Auger recombination mechanisms are identified in calculations to be the dominant mechanisms at low, intermediate and high doping densities at room temperature, respectively. Furthermore, the effects of density, capture cross-sections and energy levels (Ets) of recombination centers, and bandgaps (Egs) on the SRH lifetimes are determined and compared for the two InGaAs materials. For an n-type material, when Et is near the mid-bandgap (Eg/2), the SRH lifetime is only inversely proportional to the product of the density and the capture cross-section of the recombination centers. When Et is not near the mid-bandgap, the magnitude of Eg also plays an important role in the SRH lifetime. By increasing the In-content from 53 % in In0.53Ga0.47As to 75 % in In0.75Ga0.25As, where the bandgap narrows from 0.75 to 0.52 eV, the SRH lifetime in In0.75Ga0.25As is shortened by a factor of about 1–42 for Et < Eg/2 and 1–65 for Et > Eg/2 within the bandgap, respectively.

Study of stress-assisted nano-cutting mechanism of gallium arsenide

The high-performance manufacturing of hard-brittle materials by single-point diamond turning (SPDT) is a very active and challenging research area. The stress-assisted nano-cutting is a promising method for improving the machinability of hard-brittle materials. However, the simulation results in the existing stress-assisted nano-cutting model would contradict the actual condition due to the pre-stress being released before tool entry into the workpiece. A modified stress-assisted nano-cutting model with a virtual boundary between the workpiece and tool is proposed for the first time in this paper to investigate the nano-cutting process of GaAs material under different external stresses. The emergence of an atomic flow vortex during stress-assisted nano-cutting significantly enhances the quality of the machined surface, leading to a substantial reduction in both machined surface roughness (34.4 %) and subsurface damage (56.2 %), compared to the normal nano-cutting. By evaluating surface roughness, subsurface damage depth, morphological accuracy, cutting force, and removal efficiency, a pre-strain of 0.06 is determined to be the optimal pre-strain for stress-assisted nano-cutting. Moreover, the selection of optimal pre-strain remains unaffected by variations in the nano-cutting depth. TEM results demonstrate that the nano-cutting mechanism elucidated by the MD analysis accurately reflects the genuine deformation of the GaAs material.

Effects ofAs8structure formation on the surface morphology and internal microstructure of GaAs thin films.

Gallium arsenide (GaAs) materials have the advantages of high electron mobility, electron saturation drift rate, and other irreplaceable semiconducting properties. They play an important role in the electronics, solar and other fields. However, during GaAs film sedimentary growth, As atoms can undergo segregation to formAs8clusters because of the influence of external factors, which affect the surface morphology and internal structure of these films. In this study, a series of investigations on the deposition and growth of GaAs crystal films were performed. Additionally, the deposition and growth of GaAs thin films were simulated using molecular dynamics. The influence of As8clusters on the surface morphology and internal structure of GaAs films at different incidence angles, velocities and substrate temperatures was studied by using 'defect analysis technology' and 'diamond structure identification' in open source software, along with surface roughness and radial distribution function. Results show that with increasing incident angle, the number ofAs8clusters decreases and film density increases. Increasing incident velocity increases the irregular movement ofAs8clusters in air, and their deposition on the film surface affects the morphology of the film, and the surface roughness increases first and then decreases. Additionally, we investigated the effect of different substrate temperatures on the film surface. Results show that at a substrate temperature of 1173 K, the number ofAs8clusters in the film decreases or the As8clusters disappear, heterogeneous nucleation occurs in the film, and the crystallization rate increases. Although the dislocation line associated with nucleation may affect the mechanical and optical properties of the film, it considerably reduces the annealing effort after the deposition and growth.

Molecular dynamics simulation of the scratching process of GaAs with different crystal orientations.

In order to further improve the manufacturing technology of resonator facet of GaAs (gallium arsenide)-based laser, the scratching process of GaAs was simulated by molecular dynamics. Models of GaAs crystals with different orientations, including GaAs [100], GaAs [110], and GaAs [111], were generated, followed by scratch simulations on these models. The surface characteristics of scratches, damage width, subsurface damage, stack height, and the distribution and activity characteristics of dislocations were analyzed based on the simulation results. The results show that there are obvious anisotropy in the deformation of different crystal orientation during the scratching process of GaAs. Surface features, damage width, subsurface damage, and dislocation dynamics during scraping in GaAs crystals strongly depend on crystal orientation. It was also observed that GaAs exhibits distinct characteristics of dislocation activity during the scratching process, depending on its crystal orientation. In addition, GaAs [110] crystal direction has the smallest maximum damage width and subsurface damage depth. The maximum of maximum damage width is in GaAs [100] crystal direction, and the maximum subsurface damage depth is in GaAs [111] crystal direction. In addition, the stacking height is maximum when GaAs [100] is scraped and minimum when GaAs [110] is scraped. The engraving quality of GaAs materials was investigated utilizing the LAMMPS software through molecular dynamics simulations, while observations were facilitated using the OVITO software. The MD simulation was conducted employing the NPT ensemble, with the temperature fixed at 300 K. A time step of 2 fs was utilized, and the total duration of the MD simulation spanned 600 ps.

High-Efficiency and Large-Angle Homo-Metagratings for the Near-Infrared Region

Compact photonic devices that integrate metasurfaces with light sources have been widely studied. However, experimental demonstrations of a higher efficiency of integration are still lacking. To enhance the efficiency of light sources integrated with metasurfaces, we employed a forward design optimization method and index matching between the light source and metasurface substrate to design metagratings. To optimize the overall diffraction efficiency, we manipulated the degrees of freedom in phase, the lattice constants, and the number of unit cells. The same material was utilized for the nanostructures and substrate (homo-metagrating) for index matching, while Si and GaAs materials were used for working at 1550 and 940 nm, respectively. The experimental homo-metagratings operating at 1550 nm and made of Si exhibited an overall average efficiency of 51.3% at diffraction angles of 60.3°. On the other hand, experimental homo-metagratings operating at 940 nm and made of GaAs exhibited an overall average efficiency of 52.4% at diffraction angles of 49.3°. This suggests that the future integration of metagratings with a polarization-specific laser can further enhance the overall diffraction efficiency.

Comparison of electron scattering by acoustic-phonons in two types of quantum wells with GaAs and GaN materials.

In this work, we report a detailed comparison of electron-acoustic-phonon (EAP) interaction strength in symmetric (parabolic) and asymmetric (semi-parabolic) quantum-wells (QWs) for both GaAs and GaN materials. The operator projection method will be utilized to calculate the acoustic-phonon-assisted cyclotron resonance (CR) absorption power. The EAP interaction strength is determined by measuring the full width at half maximum (FWHM) of the acoustic-phonon-assisted CR absorption peak based on the profile of the curve describing the dependence of the acoustic-phonon-assisted CR absorption power on the photon energy. The studied result reveals that the EAP interaction strengths in the symmetric and asymmetric QWs are functions of the electron temperature (ET), external magnetic field (EMF), and confined potential frequency (CPF). Namely, the larger the ET, the EMF, and the CPF, the stronger the EAP interaction strengths in the symmetric and asymmetric QWs are for both GaN and GaAs materials. More importantly, the obtained result demonstrates that under the influence of the structural (CPF) and external (ET and EMF) parameters, the EAP interaction strength in the symmetric QW is always much stronger than that in the asymmetric QW for both GaN and GaAs materials. Simultaneously, the EAP interaction strength in the GaN material is much stronger than that in the GaAs material for both the symmetric and asymmetric QWs.

Strain-modulated anomalous circular photogalvanic effect in p-type GaAs

The influence of spatial strain distribution on the anomalous circular photogalvanic effect (ACPGE) is investigated in the p-type GaAs material. By tuning the position of exerted stress, it is experimentally observed that the uniform strain related ACPGE behaves like the sine function, which resembles the non-strain situation. Whereas the gradient strain related ACPGE shows the unimodal function line shape. To explain the observations, a new theoretical model is constructed based on spin splitting of energy bands. It is demonstrated that the ACPGE could purely derive from the spin splitting effect. Besides, the combination effect of spin splitting and inverse spin Hall effect on the ACPGE is also investigated. This work reveals the importance of bands spin splitting on ACPGE, which has not been considered before.

Simulation and Characterization of an Inverter Logic Gate by Utilizing InGaAs-Based Planar Devices

Electronic circuits known as logic gates can perform basic logical operations like inverters, AND, and OR gates. These logic gates serve as the basis for digital electronics, and they are a common component in various electronic devices, such as computers, smartphones, and other types of digital systems. This research presents an inverter logic gate made of planar devices, which have significantly simpler structures than multi-layered transistors and diodes, namely the self-switching diode (SSD) and side-gated transistor (SGT). The inverter logic gate is realized by simply connecting both SSD and SGT in parallel. The electrical characteristics and performances of the inverter logic gate are assessed based on InGaAs material using SILVACO Inc.'s ATLAS device simulator software. The simulation results show that the functionality of the proposed planar inverter is comparable to that of a conventional inverter logic gate based on the standard truth table of the device. This has demonstrated the feasibility of building logic gates using a combination of SSDs and SGTs. In addition, the planar structure of SSD and SGT allows for a relatively low-cost device fabrication process as well as offering a high-frequency operation due to low parasitic elements in the devices.

Electron–interface-phonon interaction strength in Pöschl–Teller quantum wells is enhanced considerably compared to rectangular ones

We investigated the magneto-optical properties of the Pöschl–Teller GaAs/AlAs quantum well (QW) due to the electron–interface optical (IO) phonon interaction based on the optically-detected (OD) magneto–IO-phonon resonance (MIOPR) effect. The methods of the operator projection and the profile were used to calculate the MO-absorption power (MOAP) and measure the full width at half maximum (FWHM) of the OD-MIOPR peaks. The results are as follows: The well-width (LW), the temperature of the electron–phonon system (T), and the magnetic field (B) strongly affect the MOAP and the FWHM of the OD-MIOPR peaks for both the two emission and absorption cases of IO-phonons in both the materials of the well and the barrier. The FWHMs in both the materials of the well and the barrier for the absorption case of an IO-phonon are bigger than those for the emission case. The FWHM due to IO-phonon interaction in the GaAs material of the well is stronger than that in the AlAs material of the barrier for both the two IO-phonons emission and absorption cases. Especially, the result also showed that the FWHMs in the Pöschl–Teller QW are always bigger than those in the rectangular QW for the two emission and absorption cases of IO-phonons in both the GaAs and AlAs materials of the well and the barrier, respectively. Our specific results are expected to be promising data for potential applications in optoelectronic devices.

Theoretical analysis of the longitudinal mode behavior due to mode competition in bulk semiconductor lasers

The following typical longitudinal mode phenomena occur in bulk semiconductor lasers: single-mode or multimode operation for longitudinal modes, longitudinal mode suppression except for a dominant mode, asymmetry of the spectral profile of longitudinal modes, mode hopping, and dominant mode hysteresis. This article presents the theoretical occurrences of these phenomena in a unified manner by solving mode-competition equations, including nonlinear gain based on the density matrix method. We select various types of bulk semiconductor lasers for theoretical analyses, including an 850 nm GaAs material, 1.3 and 1.55 µm InGaAsP materials, and wide-striped and narrow-striped structures of an active region. These unified analyses reveal the main factors of these phenomena and the physical parameters that influence these phenomena. A good understanding of these physical parameters will help in designing bulk semiconductor lasers with the desired characteristics.

Enhancement of Terahertz radiation due to excitation of SPW on graphene strip coated on GaAs structure

The present study proposes a methodology for improving terahertz (THz) radiation through the utilisation of a laser directed towards a graphene strip that has been coated onto a GaAs structure. The presence of a non-uniform voltage results in the production of a transient current when the laser interacts with GaAs material. The generation of THz radiation is attributed to the current that is produced along the length of GaAs structures. Concurrently, a portion of the laser beam interacts with the graphene strip, inducing a surface plasma wave (SPW) that propagates along the surface of the graphene. The amplitude of the SPW experiences an exponential decay as it travels away from the interface in both the media. The impact of the transverse electric field of surface plasmon waves in graphene on the transient current in GaAs material has been observed to enhance THz radiation. The frequency of the SPW increases in a parabolic manner as the graphene strip increases with rises with rise in propagation vector. The plasmonics (Graphene plasmons: GPs) approach used for the proposed model enables us to making the emitted radiation suitable for Terahertz spectroscopy, imaging and non-destructive testing, Highspeed data transfer, Terahertz microscopy, Terahertz microscopy, Terahertz microscopy, Quantum technology.

Effect of C ion irradiation on AlGaAs/InGaAs HEMT

In this paper, the damage caused by C ion irradiation on AlGaAs/InGaAs HEMT was investigated. The projection ranges of C ions with varying energies in AlGaAs and InGaAs materials were calculated using Monte Carlo simulation. Additionally, simulations were conducted to study the radiation-induced damage caused by 50 keV, 70 keV, and 100 keV C ions incident on the basic structure of the AlGaAs/InGaAs heterojunction.The results showed that when using 70 keV energy for C ions, a higher number of vacancy defects were generated. Based on these findings, the influence of defects introduced by different irradiation doses of 70 keV C ions on the DC and RF characteristics of the device was analyzed.

Direct bonding of LiNbO3 and GaAs at room temperature by using activated Si atom layer

Heterogeneous integration of LiNbO3 and GaAs at room temperature has been achieved by using an activated Si atom interlayer, which demonstrate effectiveness in the fabrication of GaAs based LiNbO3 wafer. By using the activated Si atom interlayer as the adhesive layer, 4-inch LiNbO3 wafer is successfully directly bonded to the surface of GaAs wafer. The wafer bonding rate reaches over 95%. After bonding, the LiNbO3/GaAs bonding pair is cut into 10 × 10 mm2 square bonded chips. After annealing, the maximum bonding strength of square bonded chips exceeds 22 MPa. This means that the bonding strength of LiNbO3/GaAs wafer can be comparable to that of bulk materials. The characterization results of the bonding interface confirm that the intermediate amorphous Si layer is effective in improving the bonding strength and quality of LiNbO3/GaAs heterojunction. Heterogeneous integration of LiNbO3 with GaAs and other Ⅲ-Ⅴ compound semiconductor materials is conducive to reducing the area occupied by optical communication platforms and improving the overall efficiency of devices.

Terahertz radiation generation by laser interaction with a periodic array of GaAs structure

In the current study, a method for generating terahertz (THz) radiation using a GaAs structure array and an incident laser is proposed. When a laser beam is directed onto GaAs material, carriers are generated within the material. These carriers, under the influence of an electric field, produce a transient current as they respond to the applied field. The time-varying current is induced in short intervals of picoseconds. Consequently, this induced current functions as a dipole. The calculation of THz emission from a GaAs array involves the application of antenna theory to the photoconductive antenna. This calculation specifically considers the electron mobility constant as the sole factor during the rising of the current density. The phased array of oscillating dipoles is generating coherent terahertz (THz) radiation. The electrical current flowing along the length of these structures is accountable to produce terahertz (THz) radiation, where the entire system acts as phase-array dipole antennae. Laser interaction with a periodic array of GaAs structures has a wide range of applications across various domains, such as imaging, spectroscopy, communications, non-destructive testing, security, biomedical research, and material science.

Excitation of THz plasmonic eignmode of parallel plain waveguide by using GaAs material

A Terahertz wave incident on waveguide made up of two parallel thin metal plates sandwiching a thin region of GaAs semiconductor, excites a surface plasma wave (SPW), at the metal–semiconductor interface. As the frequency of SPW increases the real part of the propagation vector increases linearly where the imaginary part of the propagation vector decay parabolically. It is also observed that the distortion of the pulse due to the Terahertz wave (THz) has different component of different phase velocity. The proposed methodology entails the generation of terahertz plasmonic eigenmodes within a parallel planar waveguide composed of GaAs material. The areas of focus in this field include THz Waveguiding and Routing, THz Modulators and Switches, THz Sensing and Imaging and THz Integrated Photonics.

Correction: Recent advances in single crystal narrow band-gap semiconductor nanomembranes and their flexible optoelectronic device applications: Ge, GeSn, InGaAs, and 2D materials

Correction for ‘Recent advances in single crystal narrow band-gap semiconductor nanomembranes and their flexible optoelectronic device applications: Ge, GeSn, InGaAs, and 2D materials’ by Shu An et al., J. Mater. Chem. C, 2023, 11, 2430–2448, https://doi.org/10.1039/d2tc05041b.

Excitation of Thz Plasmonics Eignmode of Parallel Plain Waveguide by Using Gaas Material

Excitation of Thz Plasmonics Eignmode of Parallel Plain Waveguide by Using Gaas Material