High-performance PbS detectors sensitized from one-step sensitization

Two-step sensitization is the key technique for achieving high-performance uncooled lead-salt infrared photoconductive detectors fabricated from vapor physic deposition (VPD) method. However, the commercialization of these devices is inhibited by the intricate sensitization processes, especially the iodination step, which requires precise control over high concentrations of iodine vapor. Herein, a one-step sensitization technique was proposed to improve the reliability of lead sulfide (PbS) detectors manufactured from VPD method. Moreover, the dependence of the detectivity on sensitization parameters involving the oxygen concentration, time, and temperature, was established and interpreted based on extensive studies on the sensitization of lead salt devices. The feasibility of the simplified sensitization was demonstrated by a room-temperature peak detectivity of 2.47 × 1010 cm Hz1/2 W−1 at 2.7 μm attained at 430 °C for 10 min in 50 % oxygen ambient. The evolution of phase, microstructure and electrical properties confirms the enhanced performance results from the improvement in PbS crystal quality as well as the formation of Pb3O2I2 and Pb2(SO4)O from high-temperature recrystallization. Therefore, the one-step sensitization paves a way for accelerating commercialization of lead-salt detectors fabricated by VPD technique.