Fabrication of MoS2-Graphene Heterostructures for Application in High-Speed High-Responsivity Photodetectors
Juan Pablo Campbell Naranjo, James Xu
Department of Physics & Astronomy
Faculty Supervisor: Huizhong Xu
Atomically thin 2D transition metal dichalcogenides such as MoS2 have shown promise for use in high-efficiency photodetectors (PDs) due to their tunable band gap [1], excellent switching ratio, and high responsivity. For example, PDs based on CVD- grown monolayer MoS2 and bismuth electrode contacts have demonstrated photoresponsivities of up to 300 A W-1 at 400 nm wavelength [2]. However, applications for MoS2-based PDs are limited as their relatively low carrier mobility results in generally lower speeds. To overcome this limitation, PDs based on van der Waals heterostructures, in particular vertical MoS2-graphene heterostructures, have gained much attention in recent years [3,4]. In this study, we demonstrate the fabrication of MoS2-graphene vertical heterostructure photodetectors based on mechanically exfoliated MoS2 of varying thicknesses. By exploiting the combined advantages of the high photosensitivity of MoS2, the small Schottky barrier between MoS2 and graphene [5], and the short carrier transit time of graphene; we hope to lower the photocurrent response time while maintaining high photosensitivity.