High performance position-sensitive-detector based on graphene-silicon heterojunction

TL;DR

This paper introduces a graphene-silicon heterojunction based position-sensitive detector that offers high sensitivity, fast response, and broadband operation, significantly outperforming traditional silicon PSDs in weak light detection and near-infrared wavelengths.

Contribution

The study presents a novel graphene-silicon heterostructure PSD with enhanced responsivity, ultra-long carrier diffusion, and broadband capabilities, advancing the performance of position-sensitive detectors.

Findings

Detects weak light at nWs level, outperforming Si p-i-n PSDs

Features fast response and low non-linearity (~3%)

Operates effectively in near-infrared wavelengths (1319 and 1550 nm)

Abstract

Position-sensitive-detectors (PSDs) based on lateral photoeffect have been widely used in diverse applications, including optical engineering, aerospace and military fields. With increasing demands in long working distance, low energy consumption, and weak signal sensing systems, the poor responsivity of conventional Silicon-based PSDs has become a bottleneck limiting their applications. Herein, we propose a high-performance passive PSD based on graphene-Si heterostructure. The graphene is adapted as a photon absorbing and charge separation layer working together with Si as a junction, while the high mobility provides promising ultra-long carrier diffusion length and facilitates large active area of the device. A PSD with working area of 8 mm x 8 mm is demonstrated to present excellent position sensitivity to weak light at nWs level (much better than the limit of ~{\mu}Ws of Si p-i-n PSDs). More importantly, it shows very fast response and low degree of non-linearity of ~3%, and extends the operating wavelength to the near infrared (IR) region (1319 and 1550 nm). This work therefore provides a new strategy for high performance and broadband PSDs.