Step graded buffer for (110) InSb quantum wells grown by molecular beam epitaxy

We report on a two step buffer layer preparation for the growth of InSb quantum wells on a (110) GaAs surface. At each buffer layer step, layer conditions were optimized to produce smooth surfaces compatible with InSb quantum wells. Through varying growth rate, group V/III flux ratio, substrate temperature, and the addition of in situ annealing, we are able to grow In0.85Al0.15Sb on a GaAs substrate with an RMS surface roughness of approximately 2 nm. Surface morphology and cross-sectional transmission electron microscopy (TEM) were analyzed to understand the formation of threading dislocations, inclusions and dislocation filtering. This work presents an initial study for the growth of large lattice mismatched III-V materials on the (110) surface.