Graphene Quantum Dots Enhanced Graphene/Si Deep Ultraviolet Avalanche Photodetectors

Abstract

Deep ultraviolet photodetectors play a critical role in applications such as ozone layer monitoring and missile alert systems. This work investigates the potential of graphene quantum dots to enhance deep ultraviolet light photodetection within the graphene/Si heterojunction. The addition of graphene quantum dots not only reduces the Schottky barrier between graphene and Si but also enhances the absorption ability of deep ultraviolet light by graphene and Si. As a result, the modified junction exhibited exceptional performance metrics, including a notable responsivity of 0.21 A/W, an impressive specific detectivity of 1.13×10 ¹¹ Jones, substantial external quantum efficiency of 94.5 %, and swift response speed (23.7/47.4 ns). Elevating the reverse bias voltage increases electron kinetic energy, thereby inducing collision ionization effects in Si. Subsequent evaluations revealed a high responsivity value of 31.4 A/W and a good gain of 28, affirming the capability of the device to detect faint light signals. The successful utilization of the Gr QDs/Gr/Si heterojunction as a single-pixel imaging device underscored its prowess in imaging applications. This innovative hybrid approach opens avenues for large-scale fabrication and diverse applications in optoelectronic devices.