Effect of Substrate Orientation on MoSe<sub>2</sub>/GaAs Heteroepitaxy
Akihiro Ohtake, Yoshiki Sakuma
Abstract
Monolayer MoSe2(0001) films are epitaxially grown on the (111)B-, (110)-, and (001)-oriented GaAs substrates by molecular-beam epitaxy. We found that the lattice mismatch is not a significant factor in determining the epitaxial relationship: epitaxial MoSe2(0001) film is formed in such a way that the directions of MoSe2 and GaAs with the highest linear atomic densities are aligned with each other. The MoSe2(0001) films on GaAs(111)B and (110) show the common epitaxial relationship of MoSe2[112̅0]//GaAs[11̅0]. For the growth on GaAs(001), the highly anisotropic atomic structure of the initial GaAs(001) surface plays a key role in determining the epitaxial orientation; the MoSe2[112̅0] direction is aligned with the GaAs[110] direction but not with the orthogonal direction of GaAs[11̅0].