Response improvement of GaAs two-dimensional non-layered sheet photodetector through sulfur passivation and plasma treatment

Abstract

The two-dimensional non-layered sheets (2DNLSs) have been paid much attention because of their large surface-to-volume ratio and special photoelectric properties. However, the large surface states density introduced by surface oxides greatly hinder the performance of 2DNLSs optoelectronics devices. In this paper, the sulfur passivation and plasma treatment are performed to remove the surface states of GaAs 2DNLSs. Before surface treatment, the responsivity and detectivity of GaAs 2DNLSs photodetector are 0.1 AW-1 and 9.6 × 1010 Jones at 8 V, respectively. After sulfur passivation, the responsivity is significantly enhanced about 14 folds and the dark current is remarkably reduced. We confirm that the origin of the improvement of responsivity and the reduction of dark current is the decrease in the surface states density. Furthermore, the performances of photodetector with plasma treatment are almost same with those of sulfur passivated photodetector. This work provides efficient methods to improve the performance of materials and devices based on 2DNLSs.