Photoresponsivity of silver nanoparticles decorated graphene–silicon Schottky junction

Abstract

Here, we demonstrate the formation of silver nanoparticles (Ag-NPs) on chemical vapor deposited graphene by dissolving base Ag foil, and their integration for Schottky junction photodetector fabrication. Ag-NPs of the size 20–100 nm were directly obtained by dissolving the Ag foil of the as-synthesized graphene in a diluted HNO₃ solution. A Schottky junction is fabricated by transferring the Ag-NPs incorporated graphene onto a Si substrate. In the fabricated device, a significant photoresponse is observed with illumination of 3.6, 5.1 and 2.1 mW cm⁻² of near-infrared (1000 nm), visible (550 nm) and near ultraviolet (350 nm) light, respectively. The graphene–Si Schottky junction shows photoresponses of 122, 98 and 78 mA W⁻¹ at 550, 350 and 1000 nm, respectively. The strong photoresponse can be attributed to light interaction with the plasmonic Ag-NPs and effective graphene–Si Schottky junction. Our finding shows that enhancing the light absorption with plasmonic nanoparticles the weakest of incident light can be detected for a broad-wavelength range.