Modulating photoelectric performance of graphene/gallium arsenide nanowire photodetectors by applying gate voltage

Abstract

Here, the authors demonstrate that the performance of graphene/gallium arsenide nanowire photodetectors could be modulated by applying gate voltage on graphene. The current–voltage curves under illumination continuously shift downward when an increasing negative gate voltage is applied, while they shift upward when an increasing positive gate voltage is applied, suggesting the modulation effect of gate voltage on the Schottky barrier height. Under a small negative gate voltage of 0.06 V, the dark current, on/off ratio, responsivity, and detectivity are dramatically improved from 6.1 to 0.22 nA, 13 to 2094, 57.1 to 351.2 mA/W, and 2.2 × 108 to 7.2 × 109 cm Hz1/2/W, respectively, due to the enhancement of the Schottky barrier height. This work provides an effective way for modulating the graphene/nanowire junction properties and enabling high performance photodetectors.