Influence of multilayer graphene doping concentrations on detection properties of MLG/Mg₂Si/Si heterojunction photodetector

Abstract

This paper presents a structural model for a photodetector (PD) with a multilayer graphene (MLG)/Mg 2 Si/Si heterojunction and an examination of the impacts of MLG doping concentrations on the detection abilities of these PDs. The results show that under the conditions of different thicknesses of the monolayer, five-layer, and 10-layer grapheme (Gr), the detection properties of heterojunction PDs degrade as the doping concentrations of the MLG layer increase from 10 13 to 10 17 cm −3 , respectively. The electric field intensity at the heterojunction MLG/Mg 2 Si interface diminishes as MLG doping concentrations increase. The effectiveness of photo-generated carrier separation and transfer in the space charge area at the MLG/Mg 2 Si interface therefore declines. The detection properties are outstanding when the MLG doping concentration is 10 13 cm −3 . The maximum values of peak responsivity, external quantum efficiency (EQE), detectivity (D*), and on/off ratio are found to be 0.81 A/W, 103.28%, 6.1×10 10 Jones, and 610.5, respectively. A minimum peak noise equivalent power (NEP) of 1.64×10 −11 WHz −1/2 is obtained. The results also show that PD has a great potential as a replacement for other visible and near-infrared (NIR) poisonous devices. The facts presented above provide a theoretical framework for the fabrication and application of optoelectronic devices.