Enhanced sensitivity of MoS₂:Er-based flexible near-infrared photodetectors via tellurium-induced interfacial charge transfer

The persistent photoconductive behavior caused by traps in the active materials usually weakens the sensitivity and stability of photodetectors. Herein, tellurium (Te) microwire and polyvinyl alcohol (PVA) composites were developed as functional flexible substrates to improve the near-infrared (NIR) photoresponse performance of MoS2:Er-based devices with the metal-semiconductor-metal structure. The flexible photodetector exhibits a rise/fall time of similar to 2.9-3.1 ms, a responsivity of similar to 0.28 mA W-1, and a detectivity of similar to 1.41 x 10(10) Jones under 808 nm irradiation. The enhanced mechanism can be attributed to the charge transfer between Te microwires and MoS2:Er films, which suppresses the dark current of the device and optimizes the generation process of electron-hole pairs under light illumination. Meanwhile, the flexibility of the device allows it to be employed in human heart rate monitoring. This work offers a simple and essential strategy for constructing integrated flexible NIR photodetectors with high performance.