Time response characteristics of photodetector based on graphene/n-Si heterojunction

Abstract

This study presents the time response characteristics of graphene/n-Si heterojunction photodetector that have been estimated by using the room temperature on–off measurements under 450 nm and 642 nm illumination with a frequency of 175Hz and 1kHz. We obtained rise time values of at most 12.5 ?s and 10.6 ?s for the device measured under 642 nm and 450 nm light illumination with a frequency of 1kHz, respectively. Numerical calculations at the same frequency show that the light penetration depth (L) increases with increasing ?, and the main mechanism is diffusion in the graphene layer, while the drift time is insignificant.