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

In this study, we demonstrate MoS2/n-GaN and MoS2/p-GaN vertical heterostructures using chemical vapor deposition (CVD). The few-layer MoS(2 )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 MoS(2 )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.