Influence of crystal orientation and surface termination on the growth of BiSb thin films on GaAs substrates

Abstract

We investigate the crystal growth of BiSb thin films on various GaAs substrates with different crystal orientation and surface termination. We found the non-trivial growth mode of BiSb which depends on the crystal orientation/surface termination of GaAs. While BiSb(0 0 1) can be grown epitaxially on GaAs(1 1 1)A, only textured BiSb(0 1 2) can be grown on GaAs(1 1 1)B even with the help of an ultrathin Bi buffer layer, indicating the critical role of surface termination of the GaAs(1 1 1) substrates. Meanwhile, only textured BiSb(0 0 1) thin films grow on GaAs(0 0 1) instead of BiSb(0 1 2), indicating that symmetry matching plays a little role on the growth of BiSb on GaAs(0 0 1).