GaAs-AlxGa1-xAs双势垒结构中电子共振隧穿寿命

采用转移矩阵和数值计算相结合的方法求解含时Schrodinger方程,计算了电子在双势垒结构中的构建时间和隧穿寿命.结果表明:构建时间和隧穿寿命对于描述电子隧穿时间特性同等重要.通过研究隧穿时间对结构参数的依赖情况发现,隧穿寿命随阱宽和垒厚的增加而迅速增大.     

轴向应变对双势垒结构共振隧穿的影响

首先介绍了共振隧穿理论和一种新效应--介观压阻效应,对AlxGa1-xAs/GaAl/AlxGa1-xAs共振隧穿双势垒结构的轴向施加压应变作了分析,然后计算了轴向应变对垒宽和垒高的影响,对透射系数和隧穿电流用Matlab作了仿真.发现压应变可以使隧穿电流线性增加,偏压不同电流增加的速率也不同,为设计共振隧穿器件提供了理论依据.     

GaAs-AlxGa1-xAs双势垒结构中电子共振隧穿寿命

采用转移矩阵和数值计算相结合的方法求解含时Schrodinger方程,计算了电子在双势垒结构中的构建时间和隧穿寿命.结果表明:构建时间和隧穿寿命对于描述电子隧穿时间特性同等重要.通过研究隧穿时间对结构参数的依赖情况发现,隧穿寿命随阱宽和垒厚的增加而迅速增大.     

三势垒共振隧穿结构中极大增强的光生空穴共振隧穿

研究了电子隧穿出射端嵌入1.2 μm厚n型弱掺杂GaAs层的三势垒双阱隧穿结构,观察到了隧穿峰谷比高达36的光生空穴共振隧穿峰.研究证实1.2 μm厚n型弱掺杂GaAs层在光照下产生的大量光生空穴以及空穴隧穿出射端的23 nm宽的量子阱中量子化的空穴能级对空穴隧穿谷电流的限制作用,是导致高峰谷比的光生空穴隧穿现象的主要原因.     

GaAs-AlxGa1-xAs双势垒结构中电子共振隧穿寿命

采用转移矩阵和数值计算相结合的方法求解含时Schrodinger方程，计算了电子在双势垒结构中的构建时间和隧穿寿命. 结果表明：构建时间和隧穿寿命对于描述电子隧穿时间特性同等重要. 通过研究隧穿时间对结构参数的依赖情况发现，隧穿寿命随阱宽和垒厚的增加而迅速增大.     

共振隧穿器件及其集成技术发展趋势和最新进展

介绍了共振隧穿器件及其特点,论述了该类器件及其集成技术的发展趋势和最新进展,特别是SiO 2S/iS/iO 2共振隧穿二极管及其集成电路的研制成功是一个突破性的进展。     

磁隧穿振荡研究GaAs／AlAs双势垒结构中的Γ—X电子态混合

报道了非对称ＧａＡｓ／ＡｌＡｓ双势垒结构（ＤＢＳ）中的Γ－Ｘ－Γ磁隧穿振荡现象，用磁场倒数周期求得ＡｌＡｓ层中Ｘ谷和ＧａＡｓ层中Γ谷之间的能带不连续值与通常公认值符合很好，良好的振荡特性可作为定量研究Γ－Ｘ耦合强度的灵敏的实验办法。     

共振隧穿二极管的材料结构设哥——共振隧穿器件讲座（5）

在系统细致分析RTD材料结构参数与器件特性参数关系的基础上，确立了RTD材料结构的设计原则和设计方法，并对以SI—GaAs为衬底的RTD分子束外延（MBE）材料生长结构进行了设计。所研制出的RTD参数实测结果证实了此设计方法是正确的。     

共振隧穿二极管研究进展

简要评述共振隧穿二极管（ＲＴＤ）器件研究进展。重点探讨以下问题：为什么ＲＴＤ研究经久不衰？器件理论模型达到何等水平？器件特性、结构和材料方面有哪些关键？围绕这些问题,介绍了有关基本概念,对ＲＴＤ器件物理模型和特性近来的研究成果和前景进行了分析,并提要性地和同类的其它量子器件作了比较。     

GaAs/AlAs超晶格中的TO声子限制模

本文报道在室温和非共振散射条件下,GaAs/AlAs 超晶格结构中TO声子限制模的拉曼散射测量结果.超晶格样品用MBE方法生长在<001>晶向的GaAs衬底上.在背散射条件下,具有E对称性的TO 声子是拉曼禁戒的.但是利用近布儒斯特角入射和大孔径的散射光收集透镜,我们观测到分别限制在GaAs和AlAs层中的TO声子模.其中,限制在AlAs层中的TO模是首次报道.从测量的TO声子限制模频率得到的声子色散曲线与GaAs和AlAs体材料的TO声子色散曲线进行比较,二者符合良好.进一步证明,超晶格结构的拉曼散射测量是测定晶体声子色散曲线的有效的实验方法.     

Controlling Phase-Coherent Electron Transport in III-Nitrides: Toward Room Temperature Negative Differential Resistance in AlGaN/GaN Double Barrier Structures

Resonant tunneling of electrons is important for the manufacture of high-speed electronic oscillators and the electron injection control in quantum cascade lasers. In this work, room temperature negative differential resistance (NDR) in AlGaN/GaN double barrier structure with AlN/GaN digital alloy (DA) barriers is demonstrated. The peak-to-valley current ratio (PVCR) ranges from 1.1 to 1.24 at room temperature and becomes 1.5 to 2.96 at low temperatures, whereas no NDR is observed in double barrier structures with conventional ternary AlGaN barriers. The room temperature NDR together with the high PVCR at low temperature is attributed to the suppression of alloy disorder scattering by introducing AlN/GaN DA barriers. This work presents the successful control of phase-coherent electron transport in III-nitride heterostructures and is expected to benefit the future design of nitride-based resonant tunneling structures and high-speed electronic devices.     

Wet Oxidation in a Square Sandwich Composite of GaAs/AlAs/GaAs

Wet oxidation in a square sandwich composite, GaAs/AlAs/GaAs, with varying thickness of the AlAs layer was investigated in a temperature range of 400°C–480°C. At a given temperature and time, the oxidation depth increases with increasing thickness of the AlAs layer. A model based on the boundary layer diffusion in a sandwich composite is used to interpret the thickness effect, and the theoretical predictions are in good agreement with the measured oxidation data. The theory also predicts a value of 0.53 eV ± 0.03 eV to be the difference in activation energies of water vapor diffusion in the central layer AlAs and the outer layers GaAs in the temperature range studied. Such a difference remains to be verified experimentally.     

Negative differential perpendicular velocity in GaAs/AlAs superlattices

We investigate the doping level, hydrostatic pressure, temperature and superlattice parameter dependence of the perpendicular negative differential velocity (NDV) of GaAs/AlAs superlattices. The results show that NDV is a single Γ miniband effect. A qualitative agreement is found with Esaki's negative effective mass model, although a few limitations of this model are pointed out and some improvement is suggested.     

GaAs／AlxGa1—xAs和AlxGa1—xAs／AlAs超晶格的喇曼散射对比研究

报道不同层厚的ＡｌＡｓ／ＡｌｘＧａ１－ｘＡｓ及ＧａＡｓ／ＡｌｘＧａ１－ｘＡｓ短周期超晶格的纵光学声子模的室温喇曼散射测量结果．在非共振条件下,观察到ＡｌＡｓ／ＡｌｘＧａ１－ｘＡｓ中限制在ＡｌｘＧａ１－ｘＡｓ混晶层中的类ＧａＡｓＬＯ限制模和限制在ＡｌＡｓ层中的ＡｌＡｓＬＯ限制模,还观察到ＧａＡｓ／ＡｌｘＧａ１－ｘＡｓ中限制在ＡｌｘＧａ１－ｘＡｓ混晶层中的类ＡｌＡｓＬＯ限制模和限制在ＧａＡｓ层中的ＧａＡｓＬＯ限制模．在近共振条件下,还观察到了ＡｌＡｓ／ＡｌｘＧａ１－ｘＡｓ中ＡｌＡｓ的界面模．根据线性链模型,把测量的ＬＯ限制模的频率按照ｑ＝ｍｎ＋１２πα０展开,给出了ＡｌｘＧａ１－ｘＡｓ混晶的类ＡｌＡｓ支和类ＧａＡｓ支光学声子色散曲线．     

GaAs/AlGaAs梯度折射率分别限制单量子阱结构中的光增益谱分析

对不同阱宽的梯度折射率分别限制单量子阱激光器进行了TE、TM模的光增益谱测量对于阱宽大于120A的激光器,发射光谱和光增益谱都出现双峰,分别是由n=1和n=2的子带跃迁所造成,激光振荡出现在n=2的子带跃迁。随着阱宽减小,n=1子带跃迁的饱和增益增加,使激光振荡能在n=1子带发生,而n=2子带的受激就需要比原来更大的注入才有可能。材料增益随阱宽减小呈超线性地增加,从而降低了n=1子带受激的最小腔长。因此,用较窄的量子阱(≤100A),高的端面反射率和尽可能短的腔长,就能得到很低的阈电流。TE和TM模增益谱的不同,使激光器在一定阱宽和腔损耗下具有不同的TE和TM激射波长。     

Al x Ga1 – x As/GaAs/Al x Ga1 – x As Double Quantum Well with a Thin AlAs Interwell Barrier: Structural Characterization by SIMS and XRD

An Al _x Ga_{1 – x} As/GaAs/Al _x Ga_{1 – x} As double quantum well with a thin AlAs interwell barrier is examined by SIMS and double-crystal XRD for an AlAs thickness of about 10 or 18 Å. Thickness and other structural parameters are determined for each layer. The rocking curves are found to indicate a fairly abrupt interwell barrier.     

Investigation on resonant tunneling in GaAs/AlxGa1-xAs DBD using tunneling spectroscopy

 Experimental investigation on resonant tunneling in various GaAs/Al_xGa_(1-x)As double barrier single well structures has been performed by using tunneling spectroscopy at different temperatures.The results show that in addition to resonant tunneling via GaAs well state confined by Al_xGa_(1-x)As Γ-point barrier there exists resonant tunneling via GaAs well state confined by Al_xGa_(1-x)As X-point barrier for both indirect(x>0.4)and direct(x<0.4)cases.     

Chaotic dynamics dependence on doping density in weakly coupled GaAs/AlAs superlattices

A discrete sequential tunneling model is used for studying the influence of the doping density on the dynamical behaviors in weakly coupled GaAs/AlAs superlattices.Driven by the DC bias,the system exhi...     

GaInNAs/GaAs量子阱结构基态光跃迁的能量

从理论和实验两个方面对GaInNAs/GaAs量子阱结构基态的光跃迁能量进行研究.在理论计算过程中,分别采用电子有效质量近似法和双能级推斥模型计算了GaInNAs合金的电子空穴分立能级的能量及其带隙能,讨论了由应变引起的带隙变化量.将理论计算结果与光致发光的实验结果进行比较,两者符合得很好.并简单分析了N的加入对GaInNAs合金带隙能产生的影响.