Growth and characterization of MoS2/n-GaN and MoS2/p-GaN vertical heterostructure with wafer scale homogeneity

Abstract In this study, we demonstrate MoS2/n-GaN and MoS2/p-GaN vertical heterostructures using chemical vapor deposition (CVD). The few-layer MoS2 was grown with wafer-scale homogeneity and confirmed to have n-type characteristics by sulfur vacancy. The optical band gap, Fermi level, and work function of MoS2 and GaN were extracted using Hall measurement, ultraviolet–visible absorption, and ultraviolet photoelectron spectroscopy (UPS) analysis, to derive the band diagram of the heterostructures. The band diagrams for both MoS2/n-GaN and MoS2/p-GaN heterostructures show straddling alignment (type I) and are well matched with the results of the current–voltage (I–V) measurement. The ohmic characteristic of MoS2/n-GaN was shown in the fabricated devices. In contrast, in the case of MoS2/p-GaN, diode characteristic with tunneling current at reverse bias was confirmed. Our results suggest that the electrical properties of 2D/3D heterostructure strongly depend on the doping of the 3D material.