Self-powered photodetectors based on Er-doped MoS2 film for NIR photo-communication and laser calibration

Molybdenum disulfide (MoS2) is a promising two-dimensional material for optoelectronic applications owing to its strong light-matter interactions, high carrier mobility, and ability to combine with other materials. However, the intrinsic bandgap (1.3-1.8 eV) of MoS2 limits its applications in the near-infrared (NIR) region. Herein, a heterojunction NIR photodetector based on the Er-doped MoS2 film is developed. The photodetector presents self-powered NIR response with a fast rise/fall time of similar to 9.2 mu s/similar to 168 mu s and a high detectivity of similar to 3.25 X 10(10) Jones at 980 nm. The high performance of the device is attributed to the improved separation of the photogenerated electron-hole pairs and the characteristic trapping capacity induced by Er dopants. Density functional theory calculations reveal that Er-doping introduces an additional energy level in the forbidden band of the MoS2:Er, and the Er-f electron orbital locates near its Fermi energy level, both of which contribute to the formation of photogenerated carriers. The MoS2:Er-based device with a 3-dB bandwidth of 5.4 kHz exhibits promising application potential in the NIR photo-communication field. Moreover, the laser calibration application of the high-performance photodetector is demonstrated. This work not only develops an effective strategy to enhance the NIR photoresponse of MoS2 films but also extends the application of MoS2-based devices.