Thi Uyen Tran, Wonkil Sakong, Seong Chu Lim* "Control of the photocurrent generation of 2D layered Materials"
The bandgap determines the detection range of photodetectors. In this presentation, we discuss how we can extend this limit by controlling the electrical properties of sensing materials. In the case of MoS2, the variation of the gate (Vgs) and source-drain (Vds) bias can result in the metal-insulator transition, contributing to dramatic changes in photocurrent generation under laser irradiation. For instance, when MoS2 exhibits metallic behavior, the mid-IR can be detected via intraband absorption from free carriers in the conduction band. In contrast, visible light can be sensed via interband transition when it becomes a semiconductor. In addition, we will discuss the control of the photocurrent generation mechanism from 2D Te/ReS2 heterostructures from the photovoltaic to either photo-thermoelectric or the combined photovoltaic and photo-thermoelectric generation.