Enhancement of light-induced resistance effect in the nanostructure of Ag/graphene based on the n-type silicon

Abstract

The direct coupling of material properties across a nanoscale interface is a promising route to achieve the functionality unavailable in bulk materials. Graphene is a kind of sp2 hybridized carbon monolayer and has been investigated in many applications due to its high charge-carrier mobility. In this paper, a type of enhanced light-induced resistance effect (LRE) is observed in the structure of Ag/graphene/n-type Si. This effect features a remarkable linear resistance change with a sensitivity of 4.39 kΩ/mm when a laser moves along the surface of the structure. With the optimal thickness of the Ag film, the resistance change ratio of LRE can reach 472%, which is significantly higher than the Ag/Si control sample (6.4%), showing an obvious graphene-induced enhancement. Photocarriers' diffusion and recombination at the heterojunction interface are crucial for the enhancement. These findings offer an effective way to study the carrier dynamics at the heterojunction interface and will be useful in the development of graphene-based optoelectronic devices, such as laser-controlled variable resistors, laser-induced diodes, and storage devices.