Characterization of Zinc Oxide (ZnO) Thin Films Prepared by RF-Sputtering, Sol-Gel, and Evaporation Methods for Optoelectronic Applications

The structural and optical properties of Zinc Oxide (ZnO) thin films fabricated on silicon (Si) substrates using prepared by Radio-Frequency (RF) Sputtering, Sol-Gel (spin coating) and Evaporation methods have been studied and investigated. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Photoluminescence (PL) spectroscopy were used for comprehensive characterization. ZnO thin film prepared using thermal evaporation method has referred a narrow FWHM, large grain size, rough surface morphology and low tensile strain compared with the ZnO thin film prepared using RF-sputtering and sol-gel method, which may be of advantage in absorbing UV light when used as a UV detector. Additionally, the ZnO tetraleg structures are uniform and are 2.5 nm in length and 0.12 µm in width. Finally, two luminescence peaks in UV and visible region can be observed of ZnO/Si (110) thin film prepared using RF-sputtering, sol-gel and thermal evaporation methods with different peaks of intensity. blue shift with respect to energy band gap of sample prepared by thermal evaporation has been obtained.