Near-Infrared Photoresponse From Vertically Aligned MoS 2 Nanosheets/Silicon Heterostructure with Graphene Edge Contact

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have emerged as potential materials for optoelectronic applications due to their rich optical properties. While devices based solely on 2D materials are considered advantageous, integrating 2D materials with customary semiconductors can open up exciting opportunities for the design of high-performance devices. In this context, herein, we present a 2D/3D MoS2/silicon photodetector design, featuring vertically aligned MoS2 nanosheets grown directly on surface-textured n-type silicon as the photosensing platform and a transferred graphene layer as a transparent van der Waals (vdW) edge contact. Surface texturing changes the chemically inert planar silicon surface to a pyramidal textured surface, which provides colossal nucleation sites for the growth of MoS2, and improves the light trapping ability through multiple reflections. Dark and photocurrent measurements revealed the device’s ability to operate in a self-powered mode and its high sensitivity to near-infrared (NIR) light. Ultimately, the photodetector demonstrated an outstanding detectivity on the order of 1012 Jones and a high photo-to-dark current ratio of 105 at 850 nm in the self-powered mode. These results highlight the potential of the graphene/MoS2/Si heterojunction for NIR photodetection applications.