Enhancement of the photoelectric properties of PbSe films via iodine sensitization in an oxygen-free atmosphere

A novel approach to sensitize PbSe films utilizing iodine after subjecting them to high-temperature heat treatment was investigated, resulting in a noteworthy enhancement in the optoelectronic performance of PbSe photodetectors. The role of iodine was analyzed from the morphological evolution, phase composition transformation and electrical properties change during the iodine sensitization process. The manipulation of the crystal boundary barrier is supposed to be the key role of iodine. First principles calculations explain the variation of the optical band gap from the energy band structure. In photodetection at room temperature, the maximum detectivity of the iodine sensitized films was 1.02 × 109 Jones at an iodine concentration of 1.36 × 10−5 mol/L. In addition, the high frequency switching behavior at 500 Hz showed excellent stability. The results indicate that the new method investigated can be applied to high-performance lead selenide photodetectors.