Large bandgap reduced graphene oxide (rGO) based <i>n-p</i> ⁺ heterojunction photodetector with improved NIR performance

Abstract

Integration of two-dimensional reduced graphene oxide (rGO) with conventional Si semiconductor offers novel strategies for realizing broadband photodiode with enhanced device performance. In this quest, we have synthesized large bandgap rGO and fabricated metal-free broadband (300–1100 nm) back-to-back connected np-pn hybrid photodetector utilizing drop casted n-rGO/p+-Si heterojunctions with high performance in NIR region (830 nm). With controlled illumination, the device exhibited a peak responsivity of 16.7 A W−1 and peak detectivity of 2.56 × 1012 Jones under 830 nm illumination (11 μW cm−2) at 1 V applied bias with fast response (∼460 μs) and recovery time (∼446 μs). The fabricated device demonstrated excellent repeatability, durability and photoswitching behavior with high external quantum efficiency (∼2.5 × 103%), along with ultrasensitive behavior at low light conditions.