Electroplated ZnO Thin Film: Influence of Deposition Time on Optical and Structural Properties

Abstract

Zinc oxide (ZnO) thin film, an important n-type semiconductor for various applications, needs to be prepared by a simple and low-cost method. Herein, ZnO thin films with various deposition times (1.25 min, 2.50 min, 5.00 min and 7.5 min) have been successfully fabricated by the electroplating method. The X-ray diffraction analysis demonstrates that the crystal structure of all samples was hexagonal, with the largest crystal size of 28.17 nm and a deposition time of 2.50 min. The scanning electron microscopy (SEM) analysis shows that the deposition time increased along with the more visible size distribution of the crystallite grains and the smaller, more spherical and uniform, compact coating of the substrate. It is found that increasing the deposition time from 1.25 min to 7.5 min leads to an increment of thickness from 0.84 µm to 4.4 µm. The elemental analysis reveals the presence of zinc (Zn) and oxygen (O) without impurities. The optical analysis reveals that the ZnO transmittance was greater than 95% for all deposition times. The highest bandgap energy value of the ZnO thin film is 3.24 eV at a deposition time of 1.25 min. With great optical and structural properties, our ZnO thin film has a big potential to be used for dye-sensitised solar cells (DSSC).