Investigation of atomic and electronic properties of 2D-MoS₂/3D-GaN mixed-dimensional heterostructures

We have performed density functional theory calculations to study the effects caused by the interfacial structure between 2D-MoS₂ and 3D-GaN. Two different surface terminations of GaN are considered: Ga-terminated (0001) (Ga-GaN) and N-terminated ([Formula: see text]) (N-GaN) configurations. We confirm that Rashba spin splitting occurs in band structure of MoS₂ on GaN. We also find that the surface states of GaN move to the deep position in band structure in the MoS₂/Ga-GaN case, while the surface states of GaN are hybridized with MoS₂ near the Fermi level for the MoS₂/N-GaN case. Furthermore, we investigate the variation in electronic structure of MoS₂/GaN heterostructures depending on the number of MoS₂ layers. Especially, the top layer MoS₂ of the 2L-MoS₂/GaN structures shows both n-type and p-type properties depending on the GaN surface termination. As a result, we suggest that the electrical characteristics of the 2D/3D heterostructures could be controlled by the surface terminations of substrate materials.