Investigation of structural, optical and vibrational properties of highly oriented ZnO thin film

This article deals with poly crystalline Zinc Oxide (ZnO) thin film fabricated on ultrasonicated clean glass substrate by sol-gel spin coating. X-Ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and UV-Visible spectroscopy (UV-Vis.), have been utilized to describe the fabricated ZnO film. The X-Ray diffraction (XRD) pattern infers that the ZnO thin film is polycrystalline. It is found that the prepared thin film, has hexagonal wurtzite phase with a better orientation of (002) plane at 2θ = 34.76°. The Raman spectra confirms the presence of C46v space group for the ZnO film with hexagonal wurtzite structure. The E2 (high) mode peak at 433 cm−1 in Raman spectra signifies that the ZnO thin film distinctly leans along c-axis. The A1 (TO) mode corresponding peak at 391 cm−1 could have arisen from the imperfections such as oxygen vacancy, zinc interstitial or their complexes and free carriers. The maximum absorbance has been observed in between 200 and 280 nm in the absorbance spectra of the synthesized ZnO thin film. The direct optical band gap of ZnO thin film is found to approximately 3.23 eV.