High Responsivity in Monolayer MoS2 Photodetector via Controlled Interfacial Carrier Trapping

Two-dimensional transition metal dichalcogenides have garnered much attention in potential advances in optoelectronic devices because of the enhanced photoresponsivity and tunable band gap for broadband photodetection. The photogating effect is responsible for high responsivity, which inherently includes the electrical bias stress contributing to the carrier trapping and degrades the device performance. Herein, we report a facile and effective approach to control carrier trapping, resulting in a high-responsive low-power photodetection considering monolayer MoS2 as the photoactive material. Implementing the gate bias as a stream of pulses, the photogating and photoconductive effects become simultaneously enhanced, which could provide an opportunity for obtaining high responsivity in optoelectronic devices. In consequence, this approach results in a large photoresponsivity of ∼4.2 × 103 A/W and a high photo gain of ∼11.3 × 103 with the positive gate bias stress even in the low-power illumination. Additionally, the photoresponsivity and photo gain of ∼0.7 × 103 A/W and ∼1.92 × 103, respectively, with the negative gate bias stress demonstrate the gate-tunable photoresponse. Our findings show the potential for future development of a highly responsive low-power photodetector.