Effective-mass theory for InAs/GaAs strained superlattices

By using the recently developed exact effective-mass envelope-function theory, the electronic structures of InAs/GaAs strained superlattices grown on GaAs (100) oriented substrates are studied. The electron and hole subband structures, distribution of electrons and holes along the growth direction, optical transition matrix elements, exciton states, and absorption spectra are calculated. In our calculations, the effects due to the different effective masses of electrons and holes in different materials and the strain are included. Our theoretical results are in agreement with the available experimental data.

Cyclotron-resonance mass of two-dimensional electrons in GaN/AlxGa1-xN heterostructures

The electron cyclotron-resonance (CR) mass of quasi-two-dimensional electrons in GaN/AlxGa1-xN heterostructures is studied theoretically. The correction to the CR mass due to electron-phonon interaction is investigated, taking into account band nonparabolicity, the occupation effect, and the screening of the electron-phonon coupling. The dependence of the CR mass on the electron density and on the magnetic field strength is displayed in detail, and the calculated CR mass agrees well with a recent experiment. We found that the effective electron-phonon coupling strength in GaN heterostructures is reduced below the bulk value.

Effective-mass theory for InAs/GaAs strained coupled quantum dots

In the framework of effective-mass envelope-function theory, the optical transitions of InAs/GaAs strained coupled quantum dots grown on GaAs (100) oriented substrates are studied. At the Gamma point, the electron and hole energy levels, the distribution of electron and hole wave functions along the growth and parallel directions, the optical transition-matrix elements, the exciton states, and absorption spectra are calculated. In calculations, the effects due to the different effective masses of electrons and holes in different materials are included. Our theoretical results are in good agreement with the available experimental data.

InGaAs/GaAs多量子阱SEED设计和特性研究

分析计算了InGaAs/GaAs多量子阱(SEED)的激子吸收行为,对器件的多量子阱及谐振腔结构进行了设计和理论分析, 用MOCVD系统生长了多量子阱外延材料,并且对器件的反射谱和光电流谱特性进行了测试。

InGaAs/GaAs多量子阱 SEED面阵结构特性与设计（英文）

讨论了谐振腔中的DBR对InGaAs/GaAs多量子阱SEED面阵光反射特性的影响。采用InGaAs/GaAs作为多量子阱SEED器件的有源区，从而获得了980nm工作波长。设计和分析了InGaAs/GaAs多量子阱SEED中的一种用于倒装焊的新型谐振腔结构。多量子阱材料是用MOCVD系统生长，利用微区光反射谱、PL谱以及X射线双晶衍射对多量子阱材料进行了测量和分析，测量结果表明多量子阱材料具有良好的质量，证明了器件结构的设计和分析是准确的。

Multiple Quantum Well SEED Arrays for Flip-Chip Bonding Optoelectronic Smart Pixels

于2010-11-23批量导入

GaAs/AlGaAs多量子阱FET-SEED灵巧象元

将GaAs/AlGaAs多量子阱光探测器、光调制器与GaAs场效应晶体管(FET)混合集成,构成FET-SEED灵巧像元光探测器和光调制器均为反射型自电光效应器件(SEED),光源为量子阱半导体激光器。光输入信号对光输出信号有明显的调制作用,可以导致光输出信号较大的变化。

Electro-mass multi odor sensor

For an olfactory sensor or electronic nose the task is not only to detect the object concentration, but also to recognize it. It is well known that all the elements can be identified by their charge to mass ratio e+/m. We tried to use this principle for molecular recognition. Two kinds of sensors are used simultaneously in testing. One is Quartz Crystal Microbalance (QCM) for detecting the change in mass, the other is Interdigital Electrode (IE) for detecting the change in conduction. In this paper the principle and the feasibility of this method are reported. The preliminary results on the recognition of alcohols are presented. The multisensor can be used as an instrument for research on material properties and kinetic process as well.

Electron effective mass and resonant polaron effect in CdTe/CdMgTe quantum wells

Cyclotron resonance in CdTe/CdMgTe quantum wells (QWs) was studied. Due to the polaron effect the zero-field effective mass is strongly influenced by the QW width. The experimental data have been described theoretically by taking into account electron-phonon coupling and the nonparabolicity of the conduction band. The subband structure was calculated self-consistently. The best fit was obtained for an electron-phonon coupling constant alpha = 0.3 and bare electron mass of m(b) = 0.092m(0).

Size and shape evolution of self-assembled coherent InAs/GaAs quantum dots influenced by seed layer

The size and shape Evolution of self-assembled InAs quantum dots (QDs) influenced by 2.0-ML InAs seed layer has been systematically investigated for 2.0, 2.5, and 2.9-ML deposition on GaAs(1 0 0) substrate. Based on comparisons with the evolution of InAs islands on single layer samples at late growth stage, the bimodal size distribution of InAs islands at 2.5-ML InAs coverage and the formation of larger InAs quantum dots at 2.9-ML deposition have been observed on the second InAs layer. The further cross-sectional transmission electron microscopy measurement indicates the larger InAs QDs: at 2.9-ML deposition on the second layer are free of dislocation. In addition, the interpretations for the size and shape evolution of InAs/GaAs QDs on the second layer will be presented. (C) 2001 Elsevier Science B.V. All lights reserved.

Electro-mass olfactory multi-sensor (EMMS)

For an olfactory sensor or electronic nose, the task is not only to detect the object concentration, but also to recognize it. It is well known that all the elements can be identified by their charge to mass ratio e(+)/m. We tried to imitate this principle for molecular recognition. Two kinds of sensors are used simultaneously in testing. One is quartz crystal microbalance (QCM) for detecting the change in mass, the other is interdigital electrode (IE) for detecting the change in conduction, as an electro-mass multi-sensor (EMMS). in this paper, the principle and the feasibility of this method are discussed. The preliminary results on the recognition of alcohol by EMMS coated with lipids are presented. Meanwhile, the multi-sensor can also be used as an instrument for research on some physico-chemistry problems. The change in conduction of coated membrane caused by one absorbed molecule is reported. It is found that when a QCM is coated with membrane, it still obeys the relationship Delta F (frequency change of QCM) = K Delta m (mass change of absorbed substance) and the proportional coefficient, K, depends not only on quartz properties but also on membrane characteristics as well. (C) 2000 Elsevier Science S.A. All rights reserved.

Flip-chip bonded hybrid CMOS/SEED optoelectronic smart pixels

Hybrid integration of GaAs/AlGaAs multiple quantum well self electro-optic effect device (SEED) arrays are demonstrated flip-chip bonded directly onto 1 mu m silicon CMOS circuits. The GaAs/AlGaAs MQW devices are designed for 850 nm operation. Some devices are used as input light detectors and others serve as output light modulators. The measurement results under applied biases show good optoelectronic characteristics of elements in SEED arrays. Nearly the same reflection spectrum is obtained for the different devices at an array and the contrast ratio is more than 1.2:1 after flip-chip bonding and packaging. The transimpedance receiver-transmitter circuit can be operated at a frequency of 300 MHz.