Lead selenide thin films: From first principles to in situ crystalline thin film growth by thermal evaporation

Lead selenide (PbSe) thin films were prepared on glass substrates using vacuum thermal evaporation at various substrate temperatures. The structural, optical, and electrical properties of the thin films, along with molecular thermodynamic calculations, were comprehensive investigated and analyzed. Morphological investigations, both surface and cross-sectional, indicated an evolution in PbSe thin films growth from an amorphous phase to two-dimensional layered structures, and subsequently to mixed states, culminating in a columnar crystal morphology. At a substrate temperature of 300 °C, the PbSe thin films exhibited electrical resistivity, mobility, and carrier concentration values of 1.2 × 10^–2 Ω·cm, 101 cm²V^-1s^-1, and 9.09 × 10¹⁸ cm^-3, respectively. To further elucidate the influence of temperature on the stability of the structure, molecular dynamics simulation calculations were performed. The results indicate that molecular thermal motion at high temperatures significantly alters both the internal structure and energy state of the material. This study advances the understanding of the thermal evaporation process, contributing to the development of high-performance PbSe infrared detectors.