Investigation the Anisotropic Feature Using Structural and Mechanical Profile Analysis of Zinc Oxide (ZnO) Thin Film Growth Mechanism within the Framework of Williamson-Hall Estimation by Novel Electrostatic Spray Deposition (ESD) Technique

The aim of this study is to investigate the anisotropic effect of a systematic and easy approach to nanocrystalline ZnO (nZnO) thin film growth by employing the novel ESD technique at temperatures ranging from 300 °C to 500 °C. In this work, Zinc Chloride (ZnCl2) was used as the Zn source, which was dissolved in Ethanol (CH3CH2OH) to prepare three different 0.1 M concentrations of 20 ml for spray solution by ESD on conductive In2O3:Sn (ITiO)-coated alkali-free glass substrates. Next, Hydrochloric acid (HCl) was added to the prepared ESD solution in the following order: 0.0 M, 0.005 M, and 0.015 M, respectively. X-ray Diffraction (XRD) indicates the presence of hexagonal wurtzite structure for nZnO thin film. Structural Properties (STP) of the lattice phase were revealed using Bragg’s law. Moreover, the Mechanical Properties (MEP) of nZnO nanoparticles were examined using X-ray broadening utilizing Williamson-Hall (W-H) and sizestrain plot methods. Strain, stress, and energy density parameters were computed for the diffraction peaks of all samples for high temperatures of 400 °C and, 500 °C exploiting the Uniform Deformation Model (UDM), Uniform Stress Deformation Model (USDM), Uniform Deformation Energy Density Model (UDEDM), and the Size-Strain Plot technique (SSP). The mean particle size data exhibited a near interrelationship with W-H analysis, SSP, and the Debye–Scherrer (D-S) methods at 500 °C temperature. The results from the XRD diffraction peak observations and properties analysis demonstrated the existence of an anisotropic countenance, which correlates with the excessive presence of leaving group [OH]- compounds in the ESD spray solutions. Due to excessive amount of [OH]- in the ESD spray solution, the ZnO thin film c-axis growth was suppressed and the a-axis growth was developed. The adhesion of anions was believed to be responsible for this suppression. The results and analysis also provided insight into how to develop a high-quality oxide-based crystal semiconductor that is economically viable for industrial and commercial applications of ESD-deposited semiconductor technology devices, specifically the growth mechanism for nZnO.