水平法低位错GaAs的单晶

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高压液封法生长热稳定不掺杂半绝缘GaAs

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GaAs表面和介面性质对毫米波器件性质的影响

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分子束外延高质量GaAs-GaAlAs材料研究

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GaAs/GaAlAs负阻激光器电学、光学特性综合研究

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GaAs/GaAlAs量子阱光学性质研究

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微重力条件下从溶体生长GaAs单晶及性质研究

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分子束外延GaAs-AlGaAs材料

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分子束外延GaAs/AlGaAs高速器件与光电子器件用料

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GaAs/AlGaAs量子阱红外探测器单管及四元线列

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MOCVD GaAlAs/GaAs超晶格量子阱材料的研制及应用

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高质量GaAs/AlGaAs二维电子气材料研制及其器件应用

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Electronic structure and optical gain saturation of InAs1-xNx/GaAs quantum dots

The electronic band structures and optical gains of InAs1-xNx/GaAs pyramid quantum dots (QDs) are calculated using the ten-band k . p model and the valence force field method. The optical gains are calculated using the zero-dimensional optical gain formula with taking into consideration of both homogeneous and inhomogeneous broadenings due to the size fluctuation of quantum dots which follows a normal distribution. With the variation of QD sizes and nitrogen composition, it can be shown that the nitrogen composition and the strains can significantly affect the energy levels especially the conduction band which has repulsion interaction with nitrogen resonant state due to the band anticrossing interaction. It facilitates to achieve emission of longer wavelength (1.33 or 1.55 mu m) lasers for optical fiber communication system. For QD with higher nitrogen composition, it has longer emission wavelength and less detrimental effect of higher excited state transition, but nitrogen composition can affect the maximum gain depending on the factors of transition matrix element and the Fermi-Dirac distributions for electrons in the conduction bands and holes in the valence bands respectively. For larger QD, its maximum optical gain is greater at lower carrier density, but it is slowly surpassed by smaller QD as carrier concentration increases. Larger QD can reach its saturation gain faster, but this saturation gain is smaller than that of smaller QD. So the trade-off between longer wavelength, maximum optical, saturation gain, and differential gain must be considered to select the appropriate QD size according to the specific application requirement. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3143025]

ф2”和 ф3”非掺Si-GaAs单晶（片）研究

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Morphology and wetting layer properties of InAs/GaAs nanostructures

In this work, we present the growth of InAs rings by droplet epitaxy. A complete process from the rings formation to their density saturation has been demonstrated: A morphological evolution with the varying of the indium deposition amount has been, clearly observed. Our results indicate that there, is a critical deposition amount (similar to 1.1 ML) for the indium to form InAs dots before droplets form; there is also a critical deposition amount (similar to 1.4 ML) to form InAs ring, but it is caused by the formation of droplets as the deposition amount increases. The density of the rings saturates when the deposition amount exceeds similar to 3.3 ML; because the adsorbed indium atoms block sites for further adsorption and the following supplied In only contributes to the size increase of In droplets. Still, as the In deposition amount increases, we can find coupled quantum rings. Moreover, the wetting layer properties of these structures are studied by reflectance difference spectroscopy, which shows a complicated evolution with the In amount. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim