Influence of growth temperature on the structural and optical characteristics of PbZnS thin films

Ternary thin films have garnered significant attention due to their adjustable band gap characteristics, making them suitable for many applications. In this research, we examined the structural and optical characteristics of PbZnS thin films fabricated onto glass substrates employing the spray pyrolysis techniuqe. The films were fabricated at different temperatures ranging from 300 to 400°C. X-ray diffraction (XRD) analysis indicated that all films displayed a cubic structure with a preferred orientation along the (200) plane. From the analysis of XRD peaks, it was observed that the crystal structure initially improved with increasing temperature but then began to degrade. These films demonstrated strong absorption in the range of 350–1600 nm. The optical bandgap (Eg) values, calculated based on the relationship between the absorption coefficient and photon energy, showed slight variations around 2 eV. Notably, the band gap decreased with growth temperatures up to 350°C, then increased at higher temperatures. These fluctuations are attributed to factors such as thermal expansion, strain, defects, surface/interface effects, and changes in doping or composition.