Extraordinary linear dynamic range in laser-defined functionalized graphene photodetectors

TL;DR

This paper introduces a laser-engineered FeCl3-intercalated graphene photodetector with an exceptionally large linear dynamic range, enabling high-resolution imaging and sensing by suppressing hot-carrier effects.

Contribution

The authors develop a novel laser irradiation method to engineer photoactive junctions in intercalated graphene, significantly enhancing its linear dynamic range compared to existing devices.

Findings

LDR at least 4500 times larger than other graphene devices

Photocurrent response is purely photovoltaic with hot-carrier effects quenched

Device maintains high stability without encapsulation

Abstract

Graphene-based photodetectors have demonstrated mechanical flexibility, large operating bandwidth, and broadband spectral response. However, their linear dynamic range (LDR) is limited by graphene's intrinsichot-carrier dynamics, which causes deviation from a linear photoresponse at low incident powers. At the same time, multiplication of hot carriers causes the photoactive region to be smeared over distances of a few micro-meters, limiting the use of graphene in high-resolution applications. We present a novel method for engineer-ing photoactive junctions in FeCl3-intercalated graphene using laser irradiation. Photocurrent measured at these planar junctions shows an extraordinary linear response with an LDR value at least 4500 times larger than that of other graphene devices (44 dB) while maintaining high stability against environmental contamination without the need for encapsulation. The observed photoresponse is purely photovoltaic, demonstrating complete quenching of hot-carrier effects. These results pave the way toward the design of ultrathin photode-tectors with unprecedented LDR for high-definition imaging and sensing.