Sensitization-Engineered Uncooled Mid-infrared PbSe Photodetectors
Xingchen Zhang, Jun Ouyang, Xi Ran, Xinzheng Lan
Abstract
Polycrystalline PbSe photodetectors are capable of mid-wave infrared (MWIR) detection without cooling. The physical sputtering process is conducive to the preparation of large-area and highly homogeneous PbSe films. However, the performance of the resulting detectors remains constrained by an insufficient understanding of the sensitization mechanisms. Here, we report high-performance sputtering-processed PbSe photodetectors by exploring a two-step sensitization process. The results show that the iodination process prolongs the carrier lifetime through the synergistic effects of defect passivation, doping modulation and internal charge separation structure. In addition, the oxygen introduced during the film deposition contributes to the formation of sensitization centers that trap photogenerated holes and inhibit carrier recombination, further enhancing the photoresponse. The optimized detectors achieve a specific detectivity of 5.8 × 10 9 Jones at a cutoff wavelength of 4.3 μm under ambient conditions, supporting their potential application for MWIR detection. This work demonstrates the first case of high-performance PbSe photodetectors achieved by sputtering, which might pave the way for their future mass production and application.