A mechanism for the variation in the photoelectric performance of a photodetector based on CVD-grown 2D MoS₂

Two-dimensional transition-metal dichalcogenides are considered as promising candidates for next-generation flexible nanoelectronics owing to their compelling properties. The photoelectric performance of a photodetector based on CVD-grown 2D MoS2 was studied. It is found that annealing treatment can make the photoresponsivity and specific detectivity of the CVD-grown 2D MoS2 based photodetector increase from 0.1722 A W-1 and 1014.65 Jones to 0.2907 A W-1 and 1014.84 Jones, respectively, while vulcanization can make the rise response time and fall response time decrease from 0.9013 s and 2.173 s to 0.07779 s and 0.08616 s, respectively. A method to determine the O-doping concentration in the CVD-grown 2D MoS2 has been obtained. The criterion for the CVD-grown 2D MoS2 to transition from an oxygen-doped state to a pure state has been developed. A mechanism explaining the variation in the photoelectric performance of the CVD-grown 2D MoS2 has been proposed. The CVD-grown 2D MoS2 and the annealed CVD-grown 2D MoS2 are oxygen-doped MoS2 while the vulcanized CVD-grown 2D MoS2 is pure MoS2. The variation in the photoelectric performance of CVD-grown 2D MoS2 results from differences in the O-doping concentration and the bandgap.