  High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially
grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their
growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were
investigated by reflection high-energy electron diffraction, atomic force
microscopy, x-ray diffraction, and high resolution transmission electron
microscopy. It is found that non-vicinal GaAs (111) substrate is better than a
vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and
magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3
topological insulator films can be directly grown on a GaAs (111) substrate,
which may pave a way to fabricate topological insulator p-n junction on the
same substrate, compatible with the fabrication process of present
semiconductor optoelectronic devices.
