MBE Growth and Characterization of Strained Hg Te(111) Films on CdTe/GaAs

Strained Hg Te thin films are typical three-dimensional topological insulator materials. Most works have focused on Hg Te(100) films due to the topological properties resulting from uniaxial strain. In this study, strained Hg Te(111) thin films are grown on Ga As(100) substrates with Cd Te(111) buffer layers using molecular beam epitaxy(MBE). The optimal growth conditions for Hg Te films are determined to be a growth temperature of 160℃ and an Hg/Te flux ratio of 200. The strains of Hg Te films with different thicknesses are investigated by highresolution x-ray diffraction, including reciprocal space mapping measurements. The critical thickness of Hg Te(111) film on Cd Te/Ga As is estimated to be approximately 284 nm by Matthews' equations, consistent with the experimental results. Reflection high-energy electron diffraction and high-resolution transmission electron microscopy investigations indicate that high-quality Hg Te films are obtained. This exploration of the MBE growth of Hg Te(111) films provides valuable information for further studies of Hg Te-based topological insulators.