Effect of nitric acid concentration on the optical and surface morphology of zinc oxide (ZnO) thin films

Abstract

This present study reports on the fabrication of porous zinc oxide (ZnO) by wet chemical etching so that the ZnO can be applied in the optoelectronic devices. ZnO thin films were deposited by radio frequency (RF) sputtering technique on the glass substrate. The etchants concentrations tested in the present study were 0.01%, 0.05% and 0.1% of nitric acid (HNO3). ZnO was etched at various etching time which at 5 s, 20 s and 35 s. Then, the samples were characterized by UV–visible (UV–vis) spectrophotometer, Fourier Transform Infra-Red (FTIR) spectrophotometer, optical microscope (OM), scanning electron microscope (SEM), atomic force microscope (AFM) and x-ray diffraction (XRD) spectrometer to access their optical properties, surface morphology and phase structure. All analyses revealed the best combination of etchant concentration and etching time was 0.1% of HNO3 and 35 s.