Lattice-matched InGaAs/InP heterostructures have been grown by using metalorganic vapor phase epitaxy (MOVPE) with tertiarybutylarsine (TBAs), tertiarybutylphosphine (TBP) as the group Ⅴ sources. The results of X-ray diffraction on InGaAs/InP single herterostructure show that there is a compressive-strained interfacial layer at the InP-to-lnGaAs interface. X-ray diffraction of InGaAs/InP superlattices is successfully simulated by using the same interfacial layer. TBAs purging of InP surface has a significant influence on the interfacial strain. A novel gas switching sequence, which switches group Ⅲ to the run line earlier than TBAs, is proposed to reduce this interfacial strain. As a result,the average compressive strain of superlattices decreases, and a blue shift of photoluminescence (PL)peak energy and narrowing in PL width are obtained.
SiC substrates grown by the sublimation method still have high densities of structural defects such as dislocations, micropipes, low-angle grain boundaries, macrodefects and polytypes. Wet etching was effectively used to study the defects of SiC. Etch pit shapes of defects and their origins were discussed. Most of the defects originate in the initial growth stage. Thus to optimize the early growth conditions especially the temperature distribution is a crucial problem.
Li Juan Wang Yingmin Chen Xiufang Xu Xiangang Hu Xiaobo Jiang Minhua
Under electron beam irradiation, the in-situ formation of 2H-SiC dentritic nanocrystals from amorphous silicon carbide at room temperature was observed. The homogenous transition mainly occurs at the thin edge and on the surface of specimen where the energy obtained from electron beam irradiation is high enough to cause the amorphous crystallizing into 2H-SiC.
Li Xianxiang Hu Xiaobo Jiang Shouzheng Dong Jie Xu Xiangang Jiang Minhua
