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- differential low noise amplifier
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Elastic Properties of Suspended Conducting GaAs/AlGaAs Nanostructures by Means of Atomic Force Microscopy
摘要： This paper demonstrates the applicability of nanoindentation technique using atomic-force microscope cantilever for studying the elastic properties of suspended semiconductor structures on the basis of relatively thick GaAs/AlGaAs membranes in the case when their stiffness significantly exceeds that of the cantilever of atomic-force microscope, which is confirmed by the agreement between the experimentally determined values of both relative and absolute stiffness measured at different points of the investigated structure with theoretical predictions.
关键词： nanoelectromechanical systems,GaAs/AlGaAs,atomic-force microscopy,suspended nanostructures
更新于2025-09-19 17:15:36
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Thermostimulated THz Radiation Emission of GaAs at Surface Plasmon-Phonon Polariton Frequencies
摘要： The THz radiation reflection, absorption and emission spectra of conductive n-GaAs/air surface are considered. The influence of thermostimulated surface plasmon-phonon (SPP) polariton oscillations on THz radiation reflection, absorption and emission of high conductivity GaAs polished plates with electron density n = 7·1017 cm–3 and 4·1018 cm–3 and thickness of 350 μm is studied experimentally. The frequencies of thermostimulated transverse and longitudinal optical phonons and SPP oscillations, which characterize a heated lattice state, were determined. It is found that the heated highly doped interface layer (GaAs/air) emits the THz radiation at selected frequencies of SPP oscillations in the (7 – 8) THz and (10 – 15) THz ranges. It is shown that thermal heating of the GaAs/air interface enhances the absorption of the incident THz radiation. The huge decrease of the incident radiation reflectivity at the SPP frequencies with an increase of GaAs temperature is observed experimentally.
关键词： surface plasmon-phonon polaritons,black-body radiation,GaAs,thermostimulated THz radiation emission
更新于2025-09-19 17:15:36
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Electrical Properties of Metal-Porous GaAs Structure at Water Adsorption
摘要： This paper reports the morphological, optical, luminescent and electrical properties of electrochemically made porous GaAs in order to evaluate their humidity sensing performance. The obtained porous GaAs exhibits non-homogenous surface morphology, which consists of pyramid-shaped crystallites and micropores. Photoluminescent and FTIR study shows that the surface of such material is covered by an oxide of As and Ga. The impedance spectroscopy was applied to analyze the influence of water vapor on electrical properties of metal-porous GaAs. It was shown that water adsorption results in the Nyquist plots shift to the region of higher frequencies. In humid atmosphere resistance Rv and characteristic time of charge accumulation s are decreased by 1.4 times and 5 times, respectively; resistance Rb and capacity Cb decreased by 1.4 times and 4.4 times, respectively. The response of the metal-porous GaAs structure to the adsorption of water is attributed to the decreasing of the bulk resistivity and potential barrier height. The formed oxide layer on the surface of porous GaAs plays a dual role—it increases the ability to adsorb water molecules and prevents the surface from receiving structural degradation.
关键词： SEM,DRIFT spectrum,impedance spectroscopy,Nyquist plot,Porous GaAs,humidity sensor
更新于2025-09-19 17:15:36
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Tailored TiO <sub/>2</sub> Protection Layer Enabled Efficient and Stable Microdome Structured pa??GaAs Photoelectrochemical Cathodes
摘要： Group III–V compound semiconductors are a promising group of materials for photoelectrochemical (PEC) applications. In this work, a metal assisted wet etching approach is adapted to acquiring a large-area patterned microdome structure on p-GaAs surface. In addition, atomic layer deposition is used to deposit a TiO2 protection layer with controlled thickness and crystallinity. Based on a PEC photocathode design, the optimal configuration achieves a photocurrent of ?5 mA cm?2 under ?0.8 V versus Ag/AgCl in a neutral pH electrolyte. The TiO2 coating with a particular degree of crystallization deposited via controlled temperature demonstrates a superior stability over amorphous coating, enabling a remarkably stable operation, for as long as 60 h. The enhanced charge separation induced by favorable band alignment between GaAs and TiO2 contributes simultaneously to the elevated solar conversion efficiency. This approach provides a promising solution to further development of group III–V compounds and other photoelectrodes with high efficiency and excellent durability for solar fuel generation.
关键词： atomic layer deposition,GaAs,TiO2 coating,photocathode stability,photoelectrochemical water splitting
更新于2025-09-19 17:13:59
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Temperature Activated Dimensionality Crossover in the Nucleation of Quantum Dots by Droplet Epitaxy on GaAs(111)A Vicinal Substrates
摘要： A temperature activated crossover between two nucleation regimes is observed in the behavior of Ga droplet nucleation on vicinal GaAs(111)A substrates with a miscut of 2° towards (1ˉ1ˉ2). At low temperature (<400 °C) the droplet density dependence on temperature and flux is compatible with droplet nucleation by two-dimensional diffusion. Increasing the temperature, a different regime is observed, whose scaling behavior is compatible with a reduction of the dimensionality of the nucleation regime from two to one dimension. We attribute such behavior to a presence of finite width terraces and a sizeable Ehrlich-Schw?bel barrier at the terrace edge, which hinders adatom diffusion in the direction perpendicular to the steps.
关键词： Quantum Dots,GaAs(111)A,Dimensionality crossover,Droplet Epitaxy,Nucleation
更新于2025-09-19 17:13:59
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - InAs/GaAs Quantum Dot Intermixing by Dry Etching and Ion Implantation
摘要： In this paper, we applied the quantum dot intermixing (QDI) technique developed for 1550nm-band InAs QD to 1300nm-band InAs/GaAs QD. Two methods of defect introduction for QDI were employed such as ICP-RIE (Ar+) and ion implantation (B+). As a result, about 80nm PL wavelength peak shift was obtained for ICP-RIE when annealing was performed at 575 (cid:933), after etching down to 450 nm to the QD layer. On the other hand, about 110nm wavelength shift was obtained for B+ implantation at an acceleration voltage of 120 keV and a dose of 1.0 × 1014 /cm2 and subsequent annealing.
关键词： ion implantation,ICP-RIE,QDI,InAs/GaAs QD
更新于2025-09-19 17:13:59
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GaAs-Based Laser Diode with InGaAs Waveguide Quantum Wells
摘要： The results of studying a GaAs-based laser with InGaAs waveguide quantum wells, which operates at room temperature in the electric-pumping mode, are presented. The minimal generation threshold is 15 A. Stable lasing at a wavelength of 1010 nm is attained, and the width of the radiation pattern in the plane perpendicular to the structure layers is (10 ± 2)°.
关键词： GaAs,laser diode,quantum well,radiation pattern,waveguide
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - GaAs Grown on Si (111) by inserting metal selenides films
摘要： In this study, the crystalline improvement of GaAs grown on metal (Ga or In) selenides films is studied. We have found that the inevitable bonding between Ga and Se on the top of In2Se3 was observed. Further, the wettability of GaAs nucleus has been improved by irradiating Ga2Se3 surface with As, Ga, and Se simultaneously. The twin-domain less than 2% for 1 μm-GaAs grown on an In2Se3/Si (111)4o off-cut to [11-2] has been achieved by introducing Ga2Se3 on In2Se3 with the subsequent (As-Ga-Se) treatment.
关键词： GaAs/Si,metal selenides,Twin
更新于2025-09-19 17:13:59
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Highly indistinguishable single photons from incoherently excited quantum dots
摘要： Semiconductor quantum dots with dimensions exceeding the free-exciton Bohr radius are appealing because of their high oscillator strengths. While this property has received much attention in the context of cavity quantum electrodynamics, little is known about the degree of indistinguishability of single photons consecutively emitted by such dots and on the proper excitation schemes to achieve high indistinguishability. A prominent example is represented by GaAs quantum dots obtained by local droplet etching, which recently outperformed other systems as triggered sources of entangled photon pairs. On these dots, we compare different single-photon excitation mechanisms, and we find (i) poor indistinguishability for conventional excitation via excited states and (ii) photon indistinguishablities above 90% for both strictly resonant and for incoherent phonon-assisted excitation. Among the explored excitation schemes, optical phonon-assisted excitation allows straightforward laser rejection and is thus worth of further investigation and optimization for quantum dots embedded in high-brightness photonic structures.
关键词： quantum dots,indistinguishability,single-photon emission,GaAs,phonon-assisted excitation
更新于2025-09-19 17:13:59
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Control of a spin qubit in a lateral GaAs quantum dot based on symmetry of gating potential
摘要： We study the influence of quantum dot symmetry on the Rabi frequency and phonon-induced spin relaxation rate in a single-electron GaAs spin qubit. We find that anisotropic dependence on the magnetic field direction is independent of the choice of the gating potential. Also, we discover that relative orientation of the quantum dot, with respect to the crystallographic frame, is relevant in systems with C1v, C2v, or Cn (n ≠ 4r) symmetry. To demonstrate the important impact of the gating potential shape on the spin qubit lifetime, we compare the effects of an infinite-wall equilateral triangle, square, and rectangular confinement with the known results for the harmonic potential. In the studied cases, enhanced spin qubit lifetime is revealed, reaching almost six orders of magnitude increase for the equilateral triangle gating.
关键词： spin qubit,GaAs,spin relaxation rate,Rabi frequency,quantum dot,gating potential
更新于2025-09-19 17:13:59