Effect of buffer layer thickness and epilayer growth temperature on crystalline quality of InAs0.9Sb0.1 grown by MOCVD

InAs0.9Sb0.1 epilayers are grown on GaAs (001) substrates by metal organic chemical vapor deposition (MOCVD). In order to relax compressive strain caused by lattice mismatch between InAs0.9Sb0.1 and GaAs, we employ a two-step growth method in which low temperature (430 °C) InAs0.9Sb0.1 buffer layers with different thicknesses are introduced into the structure. Effect of the buffer layer thickness and the epilayer's growth temperature on crystalline quality of the epilayer is investigated, respectively. It is clear that there are strip pyramids paralleling with each other on most surface of the samples. The crystalline quality gets well obviously when the buffer layer thickness change from 0 to 50 nm, but it gets worse when the buffer layer thickness increases to 100 nm. It is also shown that the crystalline quality of the epilayer is improved obviously when the epilayer is grown at 500 °C, and it gets worse when the growth temperature decreases or increases.