Crystallinity Surface Uniformity Optoelectronic Materials Solar Cell Applications Semiconductor Physics

Zinc sulphide (ZnS) thin films were successfully deposited on glass substrates using an improved solution growth technique (SGT) at a constant temperature of 50 °C for three hours, with bath molarity varied between 0.03 M and 0.15 M. The optical and solid-state characteristics of the films were systematically investigated to evaluate the influence of precursor concentration on their structural and optoelectronic performance. Spectral analyses revealed that absorbance increased while transmittance generally decreased with rising molarity, indicating enhanced light absorption due to improved film density. The absorption coefficient (α) and refractive index (n) exhibited molarity-dependent variations consistent with changes in surface uniformity and crystallinity. Calculated optical band gaps (Eg) ranged between 3.47 eV and 3.77 eV, signifying direct allowed transitions typical of ZnS semiconductors. Notably, films prepared at 0.12 M displayed optimal optical properties, balancing high transmittance with suitable band gap energy for potential application in solar cells and other optoelectronic devices.
The results confirm that controlled bath concentration in SGT offers a simple and effective route to tailoring ZnS thin films with desirable optical and solid-state characteristics for functional material applications.