Liquid iodine sensitization for enhanced mid-infrared detection of lead selenide films

In pursuit of addressing the inherent challenges associated with gas partial pressure control and non-uniform diffusion of solid iodine encountered in conventional sensitization methods, this study delves into the impact of liquid sensitization on the structural and electrical properties of lead selenide (PbSe) films. The sensitization process entails iodination of PbSe films within varying concentrations of potassium iodide (KI) solutions, followed by high-temperature sensitization. The phase composition, surface morphologies, carrier concentration and mobility, and detectivity of the PbSe films after sensitization were investigated systematically. Our findings illuminate the transformative potential of liquid iodine sensitization in the modification of the crystal boundary barrier within PbSe films, thereby engendering substantial enhancements in both structural and electrical attributes. Iodine assumes a pivotal role in the orchestration of this boundary barrier modulation, which, in turn, has birthed an innovative methodology for crafting high-performance PbSe photodetectors. Remarkably, when films were sensitized with a KI concentration of 0.05 M, the maximum detectivity achieved reached an impressive 2.27 × 109 Jones. This study not only deepens our understanding of the underlying mechanisms responsible for the optoelectronic response of PbSe films but also underscores the immense potential of liquid iodine sensitization as a promising way for elevating their overall performance.