Study of optical properties of ZnS and MnZnS (ZnS/MnS) nanostructure thin films; Prepared by microwave-assisted chemical bath deposition method

The main objective of this work is the preparation of ZnS and MnZnS (ZnS/MnS) nanostructure thin films in an ammonia-free solution by microwave-assisted chemical bath deposition (MA-CBD) method and decreasing consume of energy via decreasing deposition time from several hours to several minutes compared to conventional CBD method. ZnS and MnZnS films were deposited on commercial microscope slide glass substrates using acetic acid as a safe complexing agent. Growth rate of the film thickness was obtained approximately 1.8-2.0 nm/min. The influence of [S-2/Zn2+] molar ratio on the formation, quality, and optical properties of the films was investigated. X-ray diffraction results approved the formation of MnS/ZnS hybrid films with a cubic structure for the ZnS and MnS. Atomic force microscopy (AFM) measured the average of roughness around 6.4 nm. Field emission scanning electron microscopy (FE-SEM) exhibited that the layers were dense, homogenous, and free of pinhole or crack with very small particles at about 10-40 nm. Energy-dispersive X-ray spectrometer (EDX) revealed the presence of the Mn in the ZnS thin film and confirmed the deficiency of sulfide in the films. Fluorescence (FL) emission spectra of the films showed a strong dependence on composition as well as Ypopulation (density) of defect states such as S vacancies. UV-vis results indicated that all films are highly transparent, and their band gap energy varies from 3.6eV to 3.85eV.

Automated summary

This study focused on preparing ZnS and MnZnS nanostructure thin films in an ammonia-free solution using microwave-assisted chemical bath deposition (MA-CBD) method to reduce energy consumption by decreasing deposition time. The films were successfully deposited on glass substrates with acetic acid as a safe complexing agent, showing good quality and optical properties.