δ掺杂AlGaAs/GaAs HEMT的二维量子模型

首次建立了δ掺杂AlGaAs/GaAs高电子迁移率晶体管(HEMT)的二维量子模型，这种模型考虑了HEMT器件沟道中二维电子气的量子特性。根据这个模型，应用二维数值模拟方法和自洽求解薛定谔方程和泊松方程获得了器件沟道中的二维电子浓度，同时也得到了器件沟道中的横向电场分布和横向电流密度，模拟结果表明二维电子气主要分布在异质结GaAs一侧量子阱中。详细讨论了不同栅压和不同漏压下HEMT沟道中的二维电子浓度的分布及变化。

用回熔再生长LPE工艺制备高效AlGaAs/GaAs太阳电池

于2010-11-23批量导入

MBE和MOCVD生长的AlGaAs/GaAs GRIN-SCH SQW激光器深中心的比较

应用深能级瞬态谱(DLTS)技术详细研究分子束外延(MBE)和金属有机物化学汽相淀积(MOCVD)生长的AlGaAs/GaAs激光器的深中心。结果表明,在激光器的n-AlGaAs层里除众所周知的DX中心外,还存在着较大浓度和俘获截面的深(电子或空穴)陷阱,它们直接影响着激光器的性能。

InGaAs/GaAs和InGaAs/AlGaAs应变层量子阱中的子带驰豫过程

利用时间分辨光谱技术,在11～90K温度范围研究了不同阱宽的InGaAs/GaAs和InGaAs/AlGaAs应变层量子阱子带弛豫过程,讨论了这两种量子阱材料中不同散射机制的作用。

AlGaAs/GaAs超晶格界面平整度的X射线双晶衍射研究

用X射线运动学的多层膜干涉理论,模拟计算了AlGaAs/GaAs超晶格X射线双晶衍射摇摆曲线.提出了一种具有整数分子层的界面过度层理论模型,并运用此理论研究了零级卫星峰的峰峰位的源移,过渡层对超晶格卫星峰强度的影响以及低级卫星峰的规律性消光规律.

单片集成式反应离子刻蚀沟槽耦合腔AlGaAs/GaAs激光器

于2010-11-23批量导入

分子束处延生长AlGaAs/GaAs GRINSCH SQW激光器中高温陷阱的研究

于2010-11-23批量导入

First-principles calculation of the AlAs/GaAs interface band structure using a self-energy-corrected local density approximation

We apply a self-energy-corrected local density approximation (LDA) to obtain corrected bulk band gaps and to study the band offsets of AlAs grown on GaAs (AlAs/GaAs). We also investigate the Al(x)Ga(1-x)As/GaAs alloy interface, commonly employed in band gap engineering. The calculations are fully ab initio, with no adjustable parameters or experimental input, and at a computational cost comparable to traditional LDA. Our results are in good agreement with experimental values and other theoretical studies. Copyright (C) EPLA, 2011

Excitons in undoped AlGaAs/GaAs wide parabolic quantum wells

In this work the electronic structure of undoped AlGaAs/GaAs wide parabolic quantum wells (PQWs) with different well widths (1000 and 3000 ) were investigated by means of photoluminescence (PL) measurements. Due to the particular potential shape, the sample structure confines photocreated carriers with almost three-dimensional characteristics. Our data show that depending on the well width thickness it is possible to observe very narrow structures in the PL spectra, which were ascribed to emissions associated to the recombination of confined 1s-excitons of the parabolic potential wells. From our measurements, the exciton binding energies (of a few meV) were estimated. Besides the exciton emission, we have also observed PL emissions associated to electrons in the excited subbands of the PQWs. © 2010 IOP Publishing Ltd.

Diffusion of Zn into GaAs and AlGaAs from isothermal Liquid-phase epitaxy solutions

In this work we present results of zinc diffusion in GaAs using the liquid phase epitaxy technique from liquid solutions of Ga‐As‐Zn and Ga‐As‐Al‐Zn. Using silicon‐doped n‐GaAs substrates, working at a diffusion temperature of 850 °C, and introducing a dopant concentration ranging 1018–1019 cm−3, the most important findings regarding the diffusion properties are as follows: (a) zinc concentration in the solid depends on the square root of zinc atomic fraction in the liquid; (b) the diffusion is dominated by the interstitial‐substitutional process; (c) the diffusivity D varies as about C3 in the form D=2.9×10−67C3.05; (d) aluminum plays the role of the catalyst of the diffusion process, if it is introduced in the liquid solution, since it is found that D varies as (γAsXlAs)−1; (e) the zinc interstitial is mainly doubly ionized (Zn++i); (f) the zinc diffusion coefficient in Al0.85 Ga0.15 As is about four times greater than in GaAs; (g) by means of all these results, it is possible to control zinc diffusion processes in order to obtain optimized depth junctions and doping levels in semiconductor device fabrication.

Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics

An n(++)-GaAs/p(++)-AlGaAs tunnel junction with a peak current density of 10 100Acm(-2) is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10 000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500Acm(-2) and a voltage drop at 10 000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations.