The role of arsine in the self-assembled growth of InAs/GaAs quantum dots by metal organic chemical vapor deposition

摘要

The influence of various growth parameters such as coverage, the AsH_3 flow (Ⅴ/Ⅲ ratio), and growth interrupts on the self-assembled growth of InAs/GaAs quantum dots (QDs) by metal organic chemical vapor deposition is reported. Of the various growth parameters, the AsH_3 flow has a particularly strong influence. Higher AsH_3 flows during deposition led to a faster nucleation process and larger islands, while the presence of AsH_3 after nucleation led to continued island ripening. We suggest that this is the result of increased indium redistribution from the highly strained wetting layer to the islands, and possibly between the islands, at higher AsH_3 flows. A large defect density was observed by plan-view transmission electron microscopy, whenever the growth parameters led to larger islands. Using our optimized growth conditions we are able to avoid such defect generation and still achieve a high QD density (3 X 10~(10) cm~(-2)).