Structure and morphology of 2H-MoTe2 monolayer on GaAs(111)B grown by molecular-beam epitaxy

Abstract

The structure and morphology of monolayer 2H-MoTe2 on GaAs(111)B grown by molecular-beam epitaxy have been studied using scanning tunneling microscopy, electron diffraction, and X-ray photoelectron spectroscopy. The MoTe2 film grown and annealed under the Te-rich condition is mainly composed of a pure 2H phase, while, under the Te-deficient conditions, the 2H-MoTe2 phase begins to evolve into nanowire-like structures owing to the desorption of Te. The 2H-MoTe2(0001) film on GaAs(111)B exhibits two types of energetically favorable epitaxial orientations; one is a perfect alignment of [112 ¯ 0]MoTe2 // [11 ¯ 0]GaAs, and the other shows a slight in-plane rotation of ± 0.77∘, which reduces the effective lattice mismatch between MoTe2 and GaAs.