化学气相传输法生长ZnO单晶

利用化学气相传输法生长了ZnO单晶．通过控制源区和生长端的温度梯度，使用碳辅助增强质量传尊挚应，在无籽晶自发成核的条件下，得到了晶粒尺寸达5mm×8mm的ZnO晶体．利用长有GaN层的蓝宝石号片待为籽晶，得到了直径32mm、厚4mm左右的ZnO单晶体．用光致发光谱和X射线双晶衍射研究了ZnO晶体的性质并对生长的热力学过程和现象进行了分析．

半导体激光器温度控制研究

温度对半导体激光器的特性有很大的影响.为了使半导体激光器输出功率稳定,必须对其温度进行高精度的控制.利用PID控制网络设计了温控系统,控制精度达到±0.01℃,与无PID控制网络相比,极大的提高了系统的瞬态特性,并且试验发现采用带有温控系统的半导体激光器的输出功率稳定性比没有温控系统的输出功率得到显著改善。

用GSMBE法生长匹配型GaInAsP/InP材料及量子阱、面发射激发器结构的研究

报道通过在位组分调整,配合X射线双晶衍射测试和光致发光测试,生长了与InP精确匹配的GaLnAsP(失配度达4×10~(-4)).生长了GaInAs/InP量子阱结构的光致发光半峰宽达5.72meV.实验表明源炉档板开启 后生长速率是不均匀的,这对生长量子阱和DBR结构是个值得注意的问题,经考虑生长速率变化后生长的面发射激光器结构样片的反射率谱与理论计算的结果很好地相符.

Hydrogen related defects in neutron-irradiated silicon grown in hydrogen ambient

Isochronal thermal-annealing behavior of NTD floating-zone silicon grown in hydrogen ambient (called NTD FZ(H) Si) is presented. The dependencies of resistivity and carrier mobility on annealing temperature are determined by room-temperature Hall electrical measurements. Using infrared absorption spectroscopy, hydrogen-related infrared absorption bands evolution for NTD FZ(H) Si were measured in detail. It is demonstrated that compared with NTD FZ(Ar) Si, NTD FZ(H) Si exhibits the striking features upon isochronal annealing in temperature range of 150 similar to 650 degreesC: there appears the formation of an excessive shallow donor at annealing temperature of 500 degreesC. It is shown that the annealing behavior is directly related to the reaction of hydrogen and irradiation-induced defects. The evolution of infrared absorption bands upon temperature reflects a series of complex reaction process: irradiation-induced defects decomposition, breaking of Si-H bonds, migration and aggregation of atomic hydrogen, and formation of the secondary defects. (C) 2002 Elsevier Science B.V. All rights reserved.

In situ doping of 3C-SiC grown on (0001) sapphire substrates by LPCVD

The heteroepitaxial growth of n-type and p-type 3C-SiC on (0001) sapphire substrates has been performed with a supply of SiH4+C2H4+H-2 system by introducing ammonia (NH3) and diborane (B2H6) precursors, respectively, into gas mixtures. Intentionally incorporated nitrogen impurity levels were affected by changing the Si/C ratio within the growth reactor. As an acceptor, boron can be added uniformly into the growing 3C-SiC epilayers. Nitrogen-doped 3C-SiC epilayers were n-type conduction, and boron-doped epilayers were p-type and probably heavily compensated.