GaAs／Al_0．33Ga_0．67As短周期超晶格中能带不连续性随压力的变化

利用高压光致发光方法在液氮温度下和０—３５ｋａｒ的压力范围内对不同层厚的ＧａＡｓ／Ａｌ０．３３Ｇａ０．６７Ａｓ短周期超晶格以及具有相近组份的Ａｌ０．３Ｇａ０．７Ａｓ体材料进行了系统的研究．测得Ａｌ０．３Ｇａ０．７Ａｓ体材料的Γ谷和Ｘ谷的压力系数分别为８．６ｍｅＶ／ｋｂａｒ和－．５７ｍｅＶ／ｋｂａｒ．在一定的压力范围内同时观测到了短周期超晶格中与类Γ态和类Ｘ态相关的发光峰，从而得到了类Γ态能级和类Ｘ态能级随压力的变化关系．首次获得了有关ＧａＡｓ／Ａｌ０．３３Ｇａ０．６７Ａｓ短周期超晶格能带不连续性（包括价带     

新结构高性能In_（0．3）Ga_（0．7）As／In_（0．29）Al_（0．

新结构高性能Ｉｎ_（０．３）Ｇａ_（０．７）Ａｓ／Ｉｎ_（０．２９）Ａｌ_（０．７１）Ａｓ／ＧａＡｓＨＥＭＴ研究证明，ＩｎＧａＡｓＨＥＭＴ的结构优于ＧａＡｓＭＥＳＦＥＴ和习用的ＡｌＧａＡｓ／ＧａＡｓＨＥＭＴ。在ＧａＡｓ上制备的赝配结构ＨＥＭＴ（ＰＭ－ＨＥ...     

Al0.3Ga0.22In0.48P/GaAs HBT高温特性的研究

本文研制了Ａｌ０．３Ｇａ０．２２Ｉｎ０．４８Ｐ／ＧａＡｓ高温ＨＢＴ器件,详细地研究了器件在３００Ｋ～６２３Ｋ范围内ＨＢＴ的直流电学特性。结果表明Ａｌ０．３Ｇａ０．２２Ｉｎ０．４８Ｐ／ＧａＡｓＨＢＴ器件具有良好的高温特性,在３００Ｋ～６２３Ｋ温度内,动态电流增益变化小于１０％,Ａｌ０．３Ｇａ０．２２Ｉｎ０．４８Ｐ／ＧａＡｓＨＢＴ可工作至６２３Ｋ,工作温度超过６２３Ｋ后,器件就不能正常工作,经分析发现     

MOCVD生长的高质量掺碳GaAs/AlGaAs材料的特性研究

利用低压金属有机化合物汽相淀积方法,以液态ＣＣｌ４为掺杂源生长了高质量的碳掺杂ＧａＡｓ／ＡｌＧａＡｓ外延材料,研究了ＣＣｌ４流量、生长温度和Ⅴ／Ⅲ比等因素对外延材料中的碳掺杂水平的影响．采用电化学ＣＶ方法、范德堡霍耳方法、低温光致发光谱和Ｘ射线双晶衍射回摆曲线测量等方法对碳掺杂外延材料的电学、光学特性进行了研究．实验制备了空穴浓度高达１．９×１０２０ｃｍ－３的碳掺杂ＧａＡｓ外延材料和低温光致发光谱半宽小于５ｎｍ的高质量碳掺杂Ａｌ０．３Ｇａ０．７Ａｓ外延层．在材料研究的基础上,我们以碳为Ｐ型掺杂剂生长了Ｇａ     

High－field Nonlinear Perpendicular Transport in a GaAs／Al_（0．3）Ga_（0．7）As Short－period Superlattice

Ｈｉｇｈ－ｆｉｅｌｄＮｏｎｌｉｎｅａｒＰｅｒｐｅｎｄｉｃｕｌａｒＴｒａｎｓｐｏｒｔｉｎａＧａＡｓ／Ａｌ_（０．３）Ｇａ_（０．７）ＡｓＳｈｏｒｔ－ｐｅｒｉｏｄＳｕｐｅｒｌａｔｔｉｃｅ￥ＸｕＳｈｉｎｅ（徐士杰），ＬｉｕＪｉａｎ（刘剑），ＺｈｅｎｇＨｏｕｚ...     

InGaAsP／InP异质结光电三极管的制备

介绍了ｎ－ＩｎＰ／ｐ－ＩｎＧａＡｓＰ／０－ＩｎＰ结构的异质结光电三极管制作过程，并获得了对１．３μｍ的入射光，光增益达２２０，用带尾纤的ＧａＡｓ／ＧａＡｌＡｓ发光管测量，光学增益达１４７０。     

硅基GaAs／GaAlAs平面光波导的研究

分析了金属有机化合物化学气相淀积（ＭＯＣＶＤ）ＧａＡｓ／ＧａＡｓＡｌ／ＧａＡｓ／Ｓｉ材料结构的性能，用ＭＯＣＶＤ法地硅衬底上生长了ＧａＡｓ／ＧａＡｓＡｌ／ＧａＡｓ材料，并用这种材料制备了平面光波导样品，测定了１．３μｍ，单模激光的传输损耗小于０．６５ｄＢ／ｃｍ。     

低阈值基横模脊形波导GaAs／AlGaAs单量子阱激光器

本文报道了脊形波导结构ＧａＡｓ／ＡｌＧａＡｓ量子阱激光器的研究成果．我们采用湿法化学腐蚀方法，通过对器件结构参数的优化，制备了性能优越的脊形波导ＧａＡｓ／ＡｌＧａＡｓ量子阱激光器，器件的阈值电流低于１０ｍＡ，最低值为７．３ｍＡ，而且实现了基横模工作，这是国内报道的该结构激光器的最好水平．     

In_xGa_（1－x）As／Al_yGa（1－y）As多量子阱的高压光致发光研究

用金刚石对顶砧压力装置在液氮温度下和０～４ＧＰａ的压力范围内测量了不同阱宽（１．７～１１．０ｎｍ）的ＩｎｘＧａ（１－ｘ）Ａｓ／Ａｌ（１－ｙ）Ｇａ（１－ｙ）Ａｓ（ｘ，ｙ＝０．１５，０；０．１５，０．３３；０，０．３３）多量子阱的静压光致发光谱，发现在Ｉｎ０．１５Ｇａ０．８５Ａｓ／ＧａＡｓ多量子阱中导带第一子带到重空穴第一子带间激子跃迁产生的光致发光峰能量的压力系数随阱宽的增加而减小，在Ｉｎ０．１５Ｇａ０．８５Ａｓ／Ａｌ０．３３Ｇａ０．６７Ａｓ和ＧａＡｓ／Ａｌ０．３３Ｇａ０．６７Ａｓ多量子阱中相应发光峰的压力系数随附宽的增加而增加．根据Ｋｒｏｎｉｙ－Ｐｅｎｎｅｙ模型计算了发光峰能量的压力系数随阱宽的变化关系，结果表明导带不连续性随压力的增加（减小）及电子有效质量随压力的增加是压力系数随阱宽增加而减小（增加）的主要原因．     

LP-MOCVD制备AlGaInP高亮度橙黄色发光二极管

利用ＬＰ－ＭＯＣＶＤ外延生长ＡｌＧａＩｎＰＤＨ结构橙黄色发光二极管．引入厚层Ａｌ０．７Ｇａ０．３Ａｓ电流扩展层和Ａｌ０．５Ｇａ０．５Ａｓ－ＡｌＡｓ分布布拉格反射器（ＤＢＲ）．２０ｍＡ工作条件下，工作电压１．９Ｖ，发光波长峰值在６０５ｎｍ，峰值半宽为１８．３ｎｍ，管芯平均亮度达到２０ｍｃｄ，最大２９．４ｍｃｄ，透明封装成视角（２θ１／２）１５°的ＬＥＤ灯亮度达到１ｃｄ．     

纳米Al夹层Ga_2O_3深紫外透明导电膜的研究

用磁控溅射法在室温条件下制备了Al膜、Ga2O3膜及Ga2O3/Al/Ga2O3三层膜,对其光学和电学性能进行了表征。单层Al膜厚度大于7nm时,光学透射率在近紫外光区域大于可见光区域;Ga2O3膜在深紫外光区域(<300nm)透明,光学带隙4.96eV;Ga2O3/Al/Ga2O3三层膜透射率截止波长在245nm左右,随着顶层Ga2O3厚度增加,电导率减小,紫外光透射率峰位、吸收边、截止波长红移,透射率峰值先稍微增加,然后逐渐降低。顶层Ga2O3厚度为34nm时,Ga2O3/Al/Ga2O3三层膜在275nm处的透射率达70%,电导率为3346S.cm–1。     

GaAs基InAs/AlSb二维电子气结构的生长优化

采用分子束外延设备 (MBE) , 外延生长了InAs/AlSb二维电子气结构样品.样品制备过程中, 通过优化AlGaSb缓冲层厚度和InAs/AlSb界面厚度、改变AlSb隔离层厚度, 分别对比了材料二维电子气特性的变化, 并在隔离层厚度为5nm时, 获得了室温电子迁移率为20500cm2/V·s, 面电荷密度为2.0×1012/cm2的InAs/AlSb二维电子气结构样品, 为InAs/AlSb高电子迁移率晶体管的研究和制备提供了参考依据.     

InP基功率HEMT结构材料分子束外延生长研究

从 3个层面研究了分子束外延 Al0 .48In0 .52 As/ Ga0 .47In0 .53As/ In P功率 HEMT结构材料生长技术。首先 ,通过观察生长过程的高能电子衍射 (RHEED)图谱 ,确立了 Ga0 .47In0 .53As/ In P结构表面层的 MBE RHEED衍射工艺相图 ,据此生长的单层 Si-doped Ga0 .47In0 .53As(40 0 nm) / In P室温迁移率可达 6960 cm2 / V· s及电子浓度 1 .3 3 E1 7cm- 3。其次 ,经过优化结构参数 ,低噪声 Al0 .48In0 .52 As/ Ga0 .47In0 .53As/ In P HEMT结构材料的 Hall参数达到μ30 0 K≥ 1 0 0 0 0 cm2 / V· s、2 DEG≥ 2 .5 E1 2 cm- 2 。最后 ,在此基础之上 ,降低 spacer的厚度、在 Ga0 .47In0 .53As沟道内插入 Si平面掺杂层并增加势垒层的掺杂浓度获得了功率 Al0 .48In0 .52 As/ Ga0 .47In0 .53As/ In PHEMT结构材料 ,其 Hall参数达到μ30 0 K≥ 80 0 0 cm2 / V· s、2 DEG≥ 4 .0 E1 2 cm- 2 。     

Investigation of breakdown and DC behavior in HBTs with (Al,Ga)As collector layer

We report on the realization of an InGaP-GaAs-based double heterojunction bipolar transistor with high breakdown voltages of up to 85 V using an Al/sub 0.2/Ga/sub 0.8/As collector. These results were achieved with devices with a 2.8 /spl mu/m collector doped to 6/spl times/10/sup 15/ cm/sup -3/ (with an emitter area of 60/spl times/60 /spl mu/m/sup 2/). They agree well with calculated data from a semi-analytical breakdown model. A /spl beta//R/sub SBI/ (intrinsic base sheet resistance) ratio of more than 0.5 by introducing a 150-nm-thick graded Al-content region at the base-collector heterojunction was achieved. This layer is needed to efficiently suppress current blocking, which is otherwise caused by the conduction band offset from GaAs to Al/sub 0.2/Ga/sub 0.8/As. The thickness of this region was determined by two-dimensional numerical device simulations that are in good agreement with the measured device properties.     

A study of the damage on FIB-prepared TEM samples of AlxGa1-xAs

The damage produced by focused ion beam (FIB) milling on a TEM sample of AlGaAs crystals has been studied. The damage observed on the sidewall of an AlGaAs transmission electron microscopy (TEM) sample was an amorphous layer. The thickness of the amorphous layer linearly increased with an increase in FIB accelerating voltage from 5 to 30 kV. The thickness of the amorphous layer of Al(x)Ga(1-x)As was constant at 3 nm and was independent of the Al concentration x when the accelerating voltage was below 5 kV. The thickness of the amorphous layer of Al(x)Ga(1-x)As decreased with an increase in Al concentration x when the accelerating voltage was above 5 kV. FIB milling at 5 kV effectively minimizes the thickness of the amorphous layer and also provides flat sidewalls on multilayer samples of Al(x)Ga(1-x)As that are prepared for TEM and scanning electron microscopy (SEM).     

Observation of resonant tunnelling via first excited level in double-barrier diodes

Two clear resonance peaks for each bias direction accompanying negative differential resistance are observed in the Al0.3Ga0.7/GaAs/Al0.3Ga0.7As double-barrier diode of 24 to 26 monolayer well thickness. These two peaks are found to be the resonant tunnelling through the ground and first excited energy levels in the well.     

Sheet electron concentration at the heterointerface in Al0.48In0.52As/Ga0.47In0.53As modulation-doped structures

Sheet electron concentration at the heterointerface in Al0.48In0.52As/Ga0.47In0.53As modulation-doped structures has been calculated as a function of the spacer layer thickness, the doping concentration in Al0.48In0.52As and the lattice temperature. The calculated results were compared with those for Al0.3Ga0.7As/GaAs structures and also with the experimental data. It is shown that, compared with AlGaAs/GaAs about 1.5 times higher sheet electron concentration can be obtained in AlInAs/GaInAs at the same doping level, which is in good agreement with the experimental results.     

GaAs(001)基底取向误差对GaAs/Al_(0.3)Ga_(0.7)As中局域声子的影响(英文)

We have studied the confined phonons in GaAs/Al0 3Ga0.7As superlat-tice grown by molecular beam epitaxy on oriented and misoriented GaAs (001) substrates. Raman scattering measurements have been performed at room- and low-temperatures. The results show that the phonon features in the superlattice-grown on GaAs(001) misoriented 4° toward the [110] direction are significantly different from those in the precisely oriented sample. The difference is discussed in terms of misorientation induced atomic-steps at GaAs-Al0.3Ga0.7As interfaces.     

A GaAs gate heterojunction FET

A new semiconductor-insulator-semiconductor field-effect transistor has been fabricated. The device consists of a heavily doped n-type GaAs gate with undoped (Al,Ga)As as the gate insulator, on an undoped GaAs layer. This structure gives the device a natural threshold voltage near zero, well suited for low-voltage logic. The threshold voltage is, to first order, independent of Al mole fraction and thickness of the (Al,Ga)As layer. The layers were grown by MBE and devices fabricated using a self-aligned technique involving ion-implantation and rapid thermal annealing. A transconductance of 240 mS/mm and a field-effect mobility of about 100 000 cm²/V-s were achieved at 77 K.     

Bipolar transistor with graded band-gap base

We report the first compositionally graded base bipolar transistor. The device grown by MBE incorporates a wide gap Al0.35Ga0.65As emitter (n = 2 × 1016/cm3 and a 0.4 ?m thick p+ (= 2 × 1018/cm3)base graded from Al0.20Ga0.80As to GaAs. DC current gain of 35 with flat, nearly ideal, collector characteristics are observed. Incorporation of a graded gap base gives much faster base transit times due to the induced quasi-electric field for electrons, thus allowing a precious tradeoff against the base resistance.