▎ 摘　　要

In this work, we have reported the structural model of Graphene/Mg2Si/Si heterojunction photodetector and its photoelectric performance parameters such as breakdown voltage, forward conduction voltage, spectral response, responsivity, noise equivalent power, detection degree, and on/off ratio. The simulated data of Graphene/Mg2Si/Si heterojunction photodetectors show the breakdown voltage of 22.41 V, and the forward conduction voltage of 4.81 V. It is found that our designed photodetector shows excellent performance at incident light of 685 nm. In this case, maximum responsivity, maximum detection, and maximum switching ratio are 0.96 A/W, 4.96 x 10(11) Jones, 4.9 x 10(3), respectively. Furthermore, the minimum noise equivalent power of our designed photodetector is 2.02 x 10(-12) WHz(1/2). Comparative analysis of the data of Graphene/Mg2Si/Si heterojunction photodetector with that of Mg2Si/Si photodetector led us to conclude that our designed photodetector has improved performance.