Growth of III-V Quantum Dots by Vapor-Liquid-Solid Epitaxy

9304537 Sercel将研究气-液-固(VLS)生长机制形成纳米级III-V量子点的过程。这项研究的基本目标是确定该过程的可行性。与以前的方法不同，该技术将通过在半导体衬底表面无掩模外延来产生量子点。在超高压沉淀室中，沉积在半导体衬底上的纳米级III族液态金属液滴将被砷过饱和，从而驱动III-V量子点的VLS生长。金属液滴将通过两种方法放置在生长衬底上：(1)沉积纳米级金属团簇；(2)利用电子束光刻技术熔化通过对金属薄膜进行图案化而形成的纳米级金属点阵列。尤其是后一种方法将允许制造规则阵列的GaAs和InAs量子点，用于生产周期性光学增益介质。没有表面掩蔽材料将允许外延生长更宽的带隙封装层，从而最终将该技术应用于制造诸如量子点半导体激光器的器件。直接合成三维半导体纳米结构的能力，如量子点，将使许多预期的好处得以实现。已经提出的半导体量子点材料的应用包括用作半导体激光器中的光学增益介质、用作光学开关应用的非线性介质以及用于新的合成掺杂方案。如果该方法成功，它将代表一种新的外延形式，对光电子技术具有潜在的巨大影响。***

9304537 Sercel The formation of nanometer-scale III-V quantum dots by the vapor-liquid-solid (VLS) growth mechanism will be investigated. The basic goal of the research is to establish the feasibility of the process. Unlike previous approaches, the technique will produce quantum dots by mask-free epitaxy on the surface of a semiconductor substrate. Nanometer-scale group-III liquid metal droplets deposited on semiconductor substrates will be supersaturated with arsenic in a UHV deposition chamber, driving VLS growth of III-V quantum dots. The metal droplets will be placed on the growth substrate by two methods: (1) deposition of nanometer-scale metal clusters, and (2) melting of arrays of nanometer-scale metal dots formed by patterning thin metal films using electron-beam lithography. The latter method in particular will permit fabrication of regular arrays of GaAs and InAs quantum dots for production of periodic optical gain media. The absence of surface rnasking material will permit epitaxial growth of a wider band-gap encapsulation layer, and therefore, ultimate application of the technique to fabrication of devices such as the quantum dot semiconductor lasers. %%% The ability to directly synthesize three-dimensional semiconductor nanostructures, such as quantum dots, would enable realization of a number of predicted benefits. Applications which have been proposed for semiconductor quantum dot materials include use as an optical gain medium in semiconductor lasers, as a nonlinear medium for optical switching applications and in novel synthetic doping schemes. If the approach is successful, it will represent a new form of epitaxy with potentially great impact on optoelectronics technology. ***