OPTICAL AND STRUCTURAL STUDY OF ZINC SULFIDE THIN FILMS AT VARIOUS DEPOSITION TEMPERATURES BY CHEMICAL BATH DEPOSITION METHOD

Abstract

Researcher was able to successfully deposit zinc sulfide (ZnS) thin films on glass substrates using chemical deposition method. The author employed ammonium hydroxide and hydrazine hydrate as complexing agents, which helped control the chemical reactions. Thiourea acted as the source of sulfide (S2-) ions, while zinc chloride provided the zinc (Zn2+) ions needed to form the ZnS compound. Author then characterized the structural and optical properties of the deposited ZnS thin films .The author used X-ray diffraction (XRD) to probe the crystal structure and found that the films had an amorphous (non-crystalline) nature, likely due to the very small size of the crystallites that formed. To understand the optical behavior, we performed UV-visible spectroscopy. This revealed some interesting trends - the band gap energy, which is a key property determining the material's optical abilities, decreased from 3.51eV to 3.45eV as the deposition temperature was increased from 45°C to 60°C. Interestingly, the light absorption of the films increased with higher deposition temperatures. Further analysis showed that the optimal deposition temperature for these ZnS thin films was 55°C, where the optical properties were most favorable. . Overall, this study provides valuable insights into tuning the optoelectronic characteristics of ZnS thin films by carefully controlling the deposition temperature - an important parameter in thin film fabrication. The findings could have implications for applications like solar cells, light-emitting diodes, and optical coatings.