5. Photodetectors

Photodetectors based on two-dimensional wide-bandgap semiconductors have excellent performances such as ultra-fast response speed, high responsivity, and low dark current, which have aroused extensive research interest in the field of ultraviolet detection. However, it is usually difficult to achieve UV detection with self-powered, high polarization sensitivity, low dark current, and solar blindness at the same time. To solve this problem, we propose a UV detection principle based on the photogenerated current effect. This technique was first developed to study a net valley-spin-polarized current that can be excited by circularly polarized light and, more importantly, this current can be delivered to the drain of the material under nonequilibrium transport conditions. The atomistic first-principles theory to calculate the photocurrent is implemented on NanoDCAL and includes: strong spin-orbit interactions (SOI), noncollinear spin, and electron-photon interactions (e-ph).