Infrared photodetectors based on wide bandgap two-dimensional transition metal dichalcogenides via efficient two-photon absorption

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted considerable attention due to their outstanding optoelectronic properties and ease of integration, making them ideal candidates for high-performance photodetectors. However, the excessive width of the bandgap in some 2D TMDs presents a challenge for achieving infrared photodetection. One approach to broaden the photoresponse wavelength range of TMDs is through the utilization of two-photon absorption (TPA) process. Unfortunately, the inefficiency of TPA hinders its application in infrared photodetection. In this study, we propose the design of two photodetectors utilizing high TPA coefficient materials, specifically ReSe₂and MoS₂, to exploit their TPA capability and extend the photoresponse to the near-infrared region at 1550 nm. The ReSe₂photodetector demonstrates an unprecedented responsivity of 43μA W^-1, surpassing that of current single-material TPA photodetectors. Similarly, the MoS₂photodetector achieves a responsivity of 18μA W^-1, comparable to state-of-the-art TPA photodetectors. This research establishes the potential of high TPA coefficient 2D TMDs for infrared photodetection.