Recent development on the uncooled mid-infrared PbSe detectors with high detectivity

Polycrystalline lead salt photoconductive (PC) detectors have been widely used for applications in the 1-5 mu m spectral range because of their low cost, room temperature operation and high detectivity. However, the physical mechanism of such detectors had not been un-ambiguously understood. In order to improve the performance, we proposed a charge separation junction (CSJ) model to analyze and guide our material synthesis process, which has led to PbSe PC detectors with record high detectivity. On the other hand, the performance of photovoltaic (PV) detectors using Pb-salt epitaxial films on Si substrates has been limited by their high defect density even though the ideal performance of the PbSe PV detector was theoretically proven to be higher than the most popular HgCdTe PV detectors at near room temperature, due to its low Auger recombination property. Inspired by the high material quality of self-assembled lead salt micro-crystals, we developed a novel method to produce PV detectors using PbSe micro-crystals based on our studies on the PC detector research that showed promising preliminary results.