Research on II-VI Compounds Semiconductor Lasers

（1）采用H_2Se和H_2S气体源分子束外延（GSMBE）生长了ZnCdSSe系II-VI族化合物，获得了生长低深能级发射的高质量ZnSe的生长条件。认为ZnSSe的生长与H_2S流量和固体中S的组成比有关，这表明S的粘附系数比人们认为的要大。（2）对n型和p型ZnSe的掺杂控制分别达到2 × 10 <19><-3><17><-3>~（-3）cm ~（-3）和10 ~（-3）cm ~（-3）左右。（3）ZnCdSe/ZnSSe发光二极管在77 K和300 K下脉冲电流工作时获得了绿色发光。（4）p型和n型ZnSe在400 ℃以下退火时，其电学和光学特性没有明显的退化。并且通过它，ZnCdSe/ZnSe LED的光输出提高了3到4倍。（5）理论分析了ZnCdSe/ZnSSe和ZnCdSe/MgZnSSe应变量子阱激光器的阈值电流密度，阐明了绿色和蓝色发光区的结构设计原则。（6）对MgZnSSe和ZnSe之间的能带不连续性进行了实验估计，得到Δ Ec-0.65 Δ Eg。利用该模型对MgZnSSe/ZnSe多量子垒效应进行了理论估算，结果表明异质垒增强效应为120 meV。（7）采用分子束外延技术制备了ZnCdSe/ZnSe多量子阱激光器，工作波长为482 nm，电流密度为420 A/cm ^2，与理论值符合较好。（8）研究了ZnSe/ZnSSe短周期超晶格与GaAs的晶格匹配条件。利用该方法，在不中断生长的情况下制备了MgZnSSe系半导体激光器结构。（9）这些研究已经通过口头报告宣布，准备向技术期刊提交三篇论文。

(1)ZnCdSSe system II-VI compounds were grown by gas-source molecular beam epitaxy (GSMBE) using H_2Se and H_2S gases and the growth condition for growing high quality ZnSe with low deep level emission was obtained. It was craligied that ZnSSe could be grown for the H_2S flow rate correponding to S compositional ratio in solid, thus indicating larger sticking coefficient of S compared with that people believed. (2)The doping control for n, p type ZnSe was obtained up to 2x10^<19>cm^<-3> and around 10^<17>cm^<-3>, respectively. (3)Green emission of ZnCdSe/ZnSSe light emitting diodes was obtained the pulse current operation at 77K and 300K.(4)the obvious degradation of electric and optical characteristics for p and n type ZnSe did not be observed through thermal annealing below 400Cﾟ. And by it, the light output of ZnCdSe/ZnSe LED's was improved as a factor of 3 to 4. (5)Threshold current densities of ZnCdSe/ZnSSe and ZnCdSe/MgZnSSe strain quantum well lasers were theorretically analyzed clarifying the structural design principle for green and blue emission regions. (6)The band discontinuity between MgZnSSe and ZnSe was experimentally estimated, getting DELTAEc-0.65DELTAEg. Using it, the effect ofMgZnSSe/ZnSe multi-quantum-barriers(MQBs)were theoretically estimated showing the hetero-barrier enhancement of 120meV.(7)ZnCdSe/ZnSe multi-quantum-well lasers were fabricated by molecular beam epitaxy, operating at 482nm in wavelength with 420A/cm^2, and with a good agreement with theory. The etchant suitable for etching ZnSe was found. (8)ZnSe/ZnSSe short-period superlattices were investigated having lattice matching condition with GaAs. By use of that, MgZnSSe system semiconductor laser structures were fabricated without growth interruption. (9)These researches were already announced through oral presentations, preparing for submitting three papers to technical journals.