Effect of N2/I2 atmosphere annealing sensitization on PbSe-based photodetector for NIR photodetection

Lead selenide (PbSe) detectors have garnered widespread utility in infrared detection due to their advantages of low-Russian compounding and uncooled operation. In this study, PbSe thin films were firstly deposited on glass using selenourea (SeC(NH2)2) as the selenium source by chemical bath deposition. The changes in morphology, composition, structure, and photoelectric properties of PbSe films thermally sensitized in 4 atm of O2, N2, O2/I2, and N2/I2 were investigated. It was discovered that PbI2 was supplied to the film surface following thermal sensitization in the I2 atmosphere to create a PbSe/PbI2 separation model, promoting photogenerated charge separation and enhancing PbSe optoelectronics' performance. The device's dark current is decreased to 1/136 before annealing, the on-off ratio is increased by 18.7 times, the reaction time is only a few tens of μs, and the response speed is increased by 105 times after N2/I2 thermal sensitization.