Highly efficient gas molecule-tunable few-layer GaSe phototransistors

Abstract

Herein we present a systematic study on the effects of different gas molecules on the photoelectric response of few-layer GaSe phototransistors before and after introducing defects. After introducing defects by thermal annealing, the phototransistors become largely photo-responsive (18.75 A W⁻¹) with high external quantum efficiency (EQE) (∼91.53%), high photocurrent on–off ratio, fast photo-response, and good stability in an O₂ rich environment when illuminated by 254 nm ultraviolet light.