High-Efficiency Photodetector Based on a CVD-Grown WS<sub>2</sub> Monolayer
Rakesh Prasad, Koushik Ghosh, P. K. Giri, Dai‐Sik Kim, Dilip K. Singh
Abstract
Future generation technologies demand high efficiency photodetectors to enable sensing and switching devices for ultrafast communication and machine vision. This requires direct-band gap materials with high photosensitivity, high detectivity, and high quantum efficiency. Monolayered two-dimensional-semiconductor-based photodetectors are the most promising materials for such applications, although experimental realization has been limited due to the unavailability of a high-quality sample. In the current paper, we report about a WS 2 -based photodetector having a sensitivity of 290 A W –1 upon 405 nm excitation and an incident power density as low as 0.06 mW/cm 2 . The fabricated device shows a detectivity of 52 × 10 14 with an external quantum efficiency of 89 × 10 3 %. The observed superior photoresponse parameters of the CVD-grown WS 2 -based photodetector as compared to Si-detectors establish its capability to replace the Si-photodetectors with monolayered ultrathin device having superior performance parameters.