High-performance graphene photodetector by interfacial gating

TL;DR

This paper presents a graphene/SiO2/lightly-doped-Si photodetector with interfacial gating that achieves high sensitivity and ultra-fast response, suitable for various optical applications.

Contribution

It introduces a novel interfacial gating mechanism in a graphene-based photodetector, balancing ultra-high sensitivity with rapid response time.

Findings

Detects signals below 1 nW with ~1000 A/W responsivity

Spectral response from visible to near-infrared

Response time reduced to ~400 ns

Abstract

Graphene based photo-detecting has received great attentions and the performance of such detector is stretching to both ends of high sensitivity and ultra-fast response. However, limited by the current photo-gating mechanism, the price for achieving ultra-high sensitivity is sacrificing the response time. Detecting weak signal within short response time is crucial especially in applications such as optical positioning, remote sensing, and biomedical imaging. In this work, we bridge the gap between ultra-fast response and ultra-high sensitivity by employing a graphene/SiO2/lightly-doped-Si architecture with revolutionary interfacial gating mechanism. Such device is capable to detect < 1 nW signal (with responsivity of ~1000 A W-1) and the spectral response extends from visible to near-infrared. More importantly, the photoresponse time of our device has been pushed to ~400 ns. The current device structure does not need complicated fabrication process and is fully compatible with the silicon technology. This work will not only open up a route to graphene-based high performance optoelectronic devices, but also have great potential in ultra-fast weak signal detection.