CaF_2透明衬底中生长CdS VPE单晶膜的光学双稳态(英文)

Optical bistability (OB) in semiconductors is of increasing interest in both basic and applied research. Much is known about optical nonlineari-ties and OB in CdS crystals. This paper reports, for the first time, about the optical bistability in CdS single crystal film grown on a CaF2 transparent substrate. High quality of the film has been identified by photolumines- cence and absorption. The OB is measured by 514.5nm line of Ar+ laser modulated into 6ms square light pules at room temperature. Two spikes appear at the front and back edges of transmitted light pulses. The switchins time is about 200μs at 200mW power level, smaller than the time in CdS bulk crystal at the same condition. The mechanism of the OB is due to the increasing absorption and thermal red shift of the absorption edge.     

SI-GaAs晶片的PL mapping表征技术

研究了扫描光致发光光谱（ＰＬｍａｐｐｉｎｇ）在表征半绝缘砷化镓（ＳＩ－ＧａＡｓ）材料中的应用,实验结果表明ＳＩ－ＧａＡｓ晶片的强度及ｍａｐｐｉｎｇ均匀性对器件性能有着十分密切的关系,所以在为制备器件筛选优质的ＳＩ－ＧａＡｓ材料时,除了电阻率、迁移率、位错密度,碳含量,ＥＬ２浓度及其均匀性,晶片表面质量上,ＰＬｍａｐｐｉｎｇ也是表征材料质量的一个重要参数。