Study of High-Performance Blue Semiconductor Lasers Based on Localized Excitons

激子的三维量子约束增加了激子的结合能和振子强度。这有可能提高高性能蓝色半导体激光器的光学增益。我们在超晶格中观察到由井势垒界面涨落形成的三维量子受限激子态，并提出利用这些局域激子态实现高性能蓝色半导体激光器。这项工作由三部分组成。(1)异质界面的光学特性和局域激子态受激发射的光泵浦研究。在MOVPE生长的ZnSe/ZnSSe超晶格中观察到具有单层平整度的尖锐异质界面（梯田结构）。在能量较低的阶地区观察到明显的出口吸收峰。观察到局域态的激子激发辐射。(2)发展了用原子力显微镜表征异质界面的方法，研究异质界面上的原子排列。用多探针方法验证了该方法对半导体的识别能力。(3)金属有机气相外延p型掺杂（MOVPE）。在pn异质结二极管中，在受体浓度高达10^<16>cm^<-3>的情况下，可实现p型导通和电流注入发光。

Three-dimensional quantum confinement of excitons increases exciton binding energies and oscillator strengths of excitons. This has a possibility of enhanced optical gains for high-performance blue semiconductor lasers. We have observed three-dimensionally quantum confined exciton states formed by well-barrier interface fluctuations in superlattices, and have proposed to use these localized exciton states for realizing high-performance blue semiconductor lasers.This work consists of three parts. (1) Optical characterization of heterointerfaces and study of stimulated emission from localized exciton states with photopumping. Sharp heterointerfaces with one-mono-layr flatness(terraced structure) was observed in ZnSe/ZnSSe superlattices grown by MOVPE.A clear exiton absorption peak was observed from the terrace region with the lower energy. An excitonic stiumulated emission from the localized states was observed. (2) Development of characterization method of heterointerfaces with atomic force microscope for the purpose of studying the atomic arrangement at the heterointerfaces. The capability of discriminating semiconductors was demonstrated with a multi-probe method. (3) p-Type doping with metalorganic vapor phase epitaxy (MOVPE).p-Type conduction up to the acceptor concentration of mid 10^<16>cm^<-3> and light emission with current injection in pn heterojunction diodes were demonstrated.