Dynamics of lead selenide films modification by laser annealing

Abstract

The paper considers the modification of the structure and optical properties of chalcogenide films of lead selenide (PbSe) as a result of exposure to a continuous wave (CW) laser with 405 nm wavelength. The mechanisms of oxide layer formation and the accompanying changes in the optical properties of films during laser exposure were considered. Based on the measured reflection and transmission spectra of film regions modified by laser radiation with different exposure times (1–12 s), the extinction coefficient and refractive index were calculated. The study reveals significant modifications in the films' optical constants during the early stages of laser irradiation, leading to oxidation and melting, which are further stabilized by phase transitions. Additionally, temperature field analysis showed that the film's surface temperature in the laser spot's center is strongly influenced by the time-dependent absorption capacity, especially from the 3rd second of exposure onward.