Sb2Se3 thin films have received increasing interest for their applications in optoelectronics. However, technological intervention demands a material-specific understanding of the reactivity to different environments. Both thermal annealing and laser irradiation carried out in an ambient atmosphere are expected to induce changes in the pristine crystallographic phase of Sb2Se3, causing the creation of additional secondary phases. Here, we investigate by means of Raman spectroscopy the effect of thermal annealing and laser irradiation at different fluencies on the structural and vibrational properties of Sb2Se3 thin films. The vacuum-annealed Sb2Se3 thin films at 290 °C and subjected to laser excitation power above 2 mW exhibit a secondary phase, revealing the occurrence of selenization. Further, in situ X-ray diffraction over a broad range of annealing temperatures in N2 and ambient atmospheres was …