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

We have performed density functional theory calculations to study the effects caused by the interfacial structure between 2D-MoS 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 MoS on GaN. We also find that the surface states of GaN move to the deep position in band structure in the MoS/Ga-GaN case, while the surface states of GaN are hybridized with MoS near the Fermi level for the MoS/N-GaN case. Furthermore, we investigate the variation in electronic structure of MoS/GaN heterostructures depending on the number of MoS layers. Especially, the top layer MoS of the 2L-MoS/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.