Lead Selenide Thin Films and Uncooled Midinfrared Detectors by Vapor Phase Deposition

The broad application of lead selenide (PbSe)-based uncooled midinfrared (MIR) detectors has been hindered by the nonuniformity of wafer-level films prepared by the conventional chemical bath deposition (CBD) method. Herein, using a vapor phase deposition (VPD) approach, we demonstrate the deposition of 3 in. wafer-scale uniform PbSe thin films with thicknesses of up to 1.5 μm. To trigger the MIR response, the as-grown films were sensitized at an elevated temperature in an oxygen–iodine atmosphere. We discovered that the key to spark off the MIR response of the PbSe detector originated from the self-assembled rodlike microstructures in the thin films, which can be controlled by the I2/PbSe flux ratio in the VPD process. At room temperature, the thin film detector exhibits an excellent optoelectronic performance, with detectivity up to 2.4 × 109 cm Hz1/2 W–1 achieved under optimized conditions. Our results show that the VPD method opens up a new avenue to the industrialization of uncooled lead-salt MIR detectors.