在Si衬底上Ⅱ-Ⅵ族超晶格的MOCVD生长及其光学特性研究

This research project explored a new type of optoelectronic devices of wied band gap Ⅱ-Ⅵ compounds semiconductor, which were farbricated on Si substrate by several methods for applications of integrated optoelectronics. According to the growth methods of ZnO films, the research achievements of this project can be divided into four parts. The first, ZnS, ZnSe and ZnTe epilayers were grown on Si substrats by LP-MOCVD. These epilayers with high quality were identified by XRD and PL measurements. High quality ZnCdTe-ZnTe QWs were grown on ZnO coated Si substrates by LP-MOCVD for the first time. The emission efficiency of the sample on a ZnO bufferlarer is much higher than that grown directly on the Si substrates. The second, high quality ZnO films with a c-axis-orientated wurtize structure were grown on Si substrate by PECVD. It is found that the ZnO film quality depended on the nitridiation of Si surface by NH3 plasma, the Si subtrate temperature and the gas flow rate ratio. The third, a series of MgZnO film were fabricated by sol-gel method. On Si substrate. The optical bandgap of MgZnO films can be tuned from 3.4 to 3.93 V by adjusting the Mg content. The MgZnO alloys show high thermal stability up to 1000℃. The fourth, ZnO films were fabricated on Si substrates by some methods. Such as: the nanocrystalline ZnO films on Si substrates were prepared using a simple mothod, in which a resistive thermal evaporation of Zn and a two-step annealing processes were employed; the ZnO nanoparticles were prepared using zinc ion implantation into silica followed by post-thermal annealing in oxygen; the nanocrystalline ZnO film on Si substrates were grown by cathodic electrodeposition from demethl-sulfoxide solutions containing ZnCl2. The high quality ZnO films were fabricated by above methods. The ZnO films with preferred orientation were identified by XRD measurement. The free exciton emission band of ZnO film in the UV region dominated the PL spectrum.

用低压ＭＯＣＶＤ技术在Ｓｉ硅衬底上外延生长和判别了Ⅱ－Ⅵ族外延层及超晶格。研究该材料在不同激发条件下的激子行为，包括激子与激发态的相互作用，以及由此产生的激子吸收和发射跃迁的特征。为探索可用于Ｓｉ基光电子集成用的光双稳器件和光发射器件原型提供实验途径和物理依据。