Incorporation Behaviour of Arsenic and Phosphorus in GaAsP／GaAs Grown by Solid Source Molecular Beam Epitaxy with a GaP Decomposition Source

The incorporation behaviour of arsenic and phosphorus in the GaAsP ternary alloy under phosphorus-rich conditions is studied based on the incorporation coefficient model and the growth diffusion model combined with the alloy composition data obtained by high resolution x-ray diffraction analysis. It is found that As adatoms have longer surface lifetime and longer migration length than those of P adatoms, which leads to an arsenic incorporation efficiency much higher than that of phosphorous. With the increase of arsenic flux, the surface lifetime of arsenic adatoms decreases due to the competition of As adatoms. The detailed analysis and discussion are given here.     

超晶格界面的电子反射与干涉

从电子波动的观点出发，考虑电子波在超晶格阱层／势垒层界面的反射与干涉，讨论超晶格的电子态. 提出一种计算超晶格电子态的新方法. 理论计算出的电子能态与实验结果一致.     

ELECTROLUMINESCENCE SPECTRA OF GexSi1-x/Si SINGLE QUANTUM WELL

The electroluminescence of Ge_xSi_1-x/Si single quantum well was measured at temper-atures above room temperature along the growth direction and the direction normal to it. TO and NP peaks were resolved.     

InxGa1-xAs-GaAs应变层量子阱结构的流体静压光荧光研究

本文报道了对分子束外延(MBE)生长的In_0.25Ga_0.75As-GaAs应变层量子阱结构在77K下的压力光荧光(PL)研究的结果。流体静压力从0到50kbar.,给出了In_0.25Ga_0.75As-GaAs应变层量子阱的Γ谷压力系数,实验观察到了量子阱中能级与势垒GaAs中X谷的能级交叉。通过对其压力行为的分析,给出了In_0.25Ga_0.75As-GaAs异质结的导带与价带跃变比:Q_c=△E_c:△E_v=0.68:0.32。对(InGa)As-GaAs应变量子阱常压下的理论分析与实验符合很好。本文也对Al_0.3Ga_0.70As-GaAs量子阱进行了讨论。 关键词：     

In-Si(111)界面上的电荷转移及铟原子的表面电致迁移现象

用反射式高能电子衍射仪首次观察到在Si(111)面上的一部分铟吸附原子在直流电场下,沿电场方向发生迁移的现象——表面电致迁移。根据所观察到的表面电致迁移过程,可以把吸附在Si(111)面上的铟原子的结合状态分成两类:紧靠着硅表面的一个单原子层铟与硅表面结合牢固,几乎不受电场影响,称为紧固层;在紧固层以上的铟层易受电场影响而发生表面电致迁移,称为迁移层。从铟原子的表面电致迁移率与温度的关系,求得表面质量迁移的激活能为0.43eV。用表面电导测量研究了In-Si(111)界面形成过程中的电荷转移现象。结果表明,吸附在硅表面的铟原子形成表面深施主能级。导致表面电致迁移的力是离化了的铟原子在电场中所受到的库仑力。 关键词：     

使用AlN/GaN超晶格势垒层生长高Al组分AlGaN/GaN HEMT结构

在蓝宝石衬底上生长了以AlN/GaN超晶格准AlGaN合金作为势垒的HEMT结构材料,并与传统AlGaN合金势垒样品进行了对比.在高Al组分(≥40%)情况下,超晶格势垒样品的表面形貌明显改进,电学性能特别是2DEG面电子浓度也有所改进.对超晶格势垒生长参数进行了初步优化,使得HEMT结构薄层电阻进一步降低,最后获得了251 Ω/□的薄层电阻. 关键词： AlGaN/GaN 结构 AlN/GaN超晶格 二维电子气 高电子迁移率晶体管     

Enhanced Photoluminescence of InGaN/GaN Green Light-Emitting Diodes Grown on Patterned Sapphire Substrate

Green InGaN/GaN based light-emitting diodes （LEDs） are fabricated both on planar and wet-etched patterned sapphire substrates by metalorganic vapour phase epitaxy （MOVPE）. Their photoluminescence （PL） properties of the two samples are studied. The results indicate that the PL integral intensity of the green LED on the patterned substrate is nearly two times of that on the planar one within the whole measured temperature range. The enhanced PL intensity in the green LED on the patterned substrate is shown completely contributed from the extraction efficiency, but not from the internal quantum efficiency. The conclusion is supported by temperature-dependent PL analysis on the two samples, and the mechanisms axe discussed.     

超晶格结构中电子的波动性

在温度T=77K,测量了GaAs/AlGaAs超晶格的光电流,观测到在ν=1589cm^-1有一个强电流峰,而在ν=1779,2129和2401cm^-1附近存在弱电流峰.分析认为,这些电流峰与电子的波动性有关.据电子波动理论计算出的光电流峰位置与实验测量结果相当一致 关键词： 超晶格 电子 波动性     

Effect of GaAs/GaSb Combination Strain-Reducing Layer on Self-Assembled InAs Quantum Dots

Self-assembled quantum dots capping with a GaAs/Gasb combined strain-reduced layer （CSRL） are grown by MBE. Their structural and optical properties are investigated by AFM and photoluminescence （PL）. PL measurements have shown that stronger emission about 1.3μm can be obtained by Sb irradiation and capping QDs with 3 ML GaAs/2 ML GaSh CSRL at room temperature. The full width at half maximum （FWHM） of the PL spectrum is about 20.2 meV （19.9 meV） at room temperature （2OK）, indicating that the QDs have high uniform, The result of FWHM is much better than the recently reported result, which is due to the fact that lower QD growth rate and growth interruption after the QDs deposition are adopted in our experiments.