Review of photo response in semiconductor transition metal dichalcogenides based photosensitive devices

Various performance aspects and the photocurrent generation mechanisms of photosensitive devices based on two-dimensional transition metal dichalcogenides are reviewed. The work begins with discussions on light absorption and charge separation mechanisms in TMD-based photodetectors. Then, performances of simple metal-TMDs-metal detectors are discussed in terms of responsivity and response time. Thereafter, novel photosensitive devices involving TMDs, either incorporating other materials or novel photosensitive device structure designs, are summarized, and basic ideas behind these devices to improve the photodetection performance are elaborated. Lastly, two valley degree of freedom related photoresponses, circular polarized photogalvanic effect and valley Hall effect, are presented. The review ends with prospectives of future challenges and opportunities in developing TMDs based photodetection devices.