Effect of electrolyte concentration on the structural and optical properties of ZnO

Abstract

ZnO nanorods were grown on ITO substrates with different concentration of electrolyte by electrodeposition method. Microstructure, surface topography, photoluminescence spectra, Raman spectra and water contact angle of the thin films were measured. The XRD results show all samples are hexagonal wurtzite and the intensity of diffraction peaks at (002) preferred orientation are strengthen as electrolyte concentration increase from 0.005 to 0.03 M. As the concentration increases, the average diameter, density and inclination of the ZnO nanorods increased. Room temperature photoluminescence spectras of the ZnO nanorods show a narrow UV band centering at about 377 nm and broad visible emissions around 600 nm and the UV peak intensity revealed a remarkable decreased. Raman spectras exhibit three peaks which are located at 439 cm−1, 562 cm−1 and 1095 cm−1. All samples change from hydrophobicity to hydrophilic after one hour ultraviolet (UV) irradiation.