Optical properties of nano-structured zinc oxide thin films deposited by radio-frequency magnetron sputtering at different substrate temperatures

ZnO thin films were deposited by Rf Magnetron sputtering on glass substrates at various deposition temperature in the range of 100-400°C. The thin films characterized using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and UV-VIS-NIR spectrophotometer for morphology and optical properties study. All the films are transparent in the visible region (400-800 nm) with average transmittance above 90 %. The optical transmittance and band gap energy, calculated from the spectra of optical absorbance, show a significant dependence on the growth temperature. As for the sample grown at 100°C, the average transmittance is about 90% in the visible wavelength range and the band gap is estimated to be 3.249 eV.