Investigation of the Solution-Dependent Zinc Oxide (ZnO) Thin Film Growth Process by the Electrostatic Spray Deposition (ESD) Method

Abstract

The present study describes a facile route of nanocrystalline (NC) ZnO growth using the solution-dependent ESD method at temperatures ranging from 300˚C to 500˚C. Zinc chloride (ZnCl 2 ) was used as the Zn source, and it was dissolved in ethanol (CH 3 CH 2 OH) to prepare the various ESD spray solutions. The crystallographic orientations of the ZnO thin films were evaluated using X-ray diffraction (XRD). The morphologies of the ZnO films were observed by scanning electron microscopy (SEM). In order to check for the material composition of ZnO films, the energy-dispersive X-ray spectroscopy (EDX) analysis was performed. XRD and Raman show that ZnO thin films have a hexagonal wurtzite structure and point out a possible complex reaction mechanism due to the increase in H 2 O ratio in the solution. The microstructural parameters (MIP), namely, lattice parameters, were revealed using Bragg’s law. Meanwhile, other MIPs, such as bond length, positional parameters of the lattice phase, full width at half maximum, crystallite sizes, lattice strain, and lattice dislocation density, were estimated using the Debye-Scherrer method (D-S). The findings indicate that the ratio of added deionized water (H 2 O) suppresses the c-axis crystal growth of ZnO thin films. The adhesion of anions is thought to be responsible for this suppression. The results and analysis gave clues about how to develop a high-quality oxide-based crystal semiconductor that is economically viable for industrial and commercial applications of the ESD technique to semiconductor technology devices.