Dual-wavelength photodetector based on monolayer MoS2/GaN heterostructure

Gallium nitride (GaN) has been confined to ultraviolet (UV) detectors due to its semiconductor characteristic with bandgap of 3.4 eV. In this work, we epitaxially grow two-dimensional (2D) molybdenum disulfide (MoS2) on top of three-dimensional (3D) p-GaN (0001) substrate by confined-space chemical vapor deposition (CVD) method. The optical microscopic and spectroscopic analyses of as-grown triangular monolayer (ML) MoS2 are presented. The fabricated photodetector based on 2D MoS2/3D p-GaN hybrid heterostructure exhibit excellent rectify behavior and dual-wavelength photoresponse, which are measured by current-voltage (I-V) characteristics under dark condition and illumination. In addition, the density functional theory (DFT) calculated results demonstrate the formation of type II band arrangement and enhanced optical properties of the 2D/3D hybrid heterostructure. This work illustrates that the hybrid heterostructure prepared by epitaxially grown 2D materials provides feasible methods for the promising dual-wavelength photodetectors of group III-Nitrides.