Epitaxial growth of monolayer MoSe2 on GaAs

Abstract

We realized 1–4 monolayer MoSe2 films on Se-terminated GaAs (111)B 2-in. substrates by molecular beam epitaxy. Atomically flat GaAs wafers were prepared by the migration-enhanced epitaxy method, and MoSe2 layers were successfully grown on Se-terminated GaAs (111)B surfaces with layer-number control over the entire wafer area. The obtained MoSe2 crystal is well aligned on the GaAs (111)B surface. The quasi-van der Waals gap formed between a Se-terminated GaAs (111)B surface and MoSe2 was directly observed with a scanning transmission electron microscope. All A1g Raman peaks from 93 points on 2-in. monolayer MoSe2 are distributed within 0.25 cm−1, indicating excellent spatial uniformity.