Optical Properties of ZnO thin films prepared by Sol-gel method

In this work studied the optical properties of ZnO thin films prepared by sol gel spin coating process. A sol has been prepared by reacting Zinc acetate dihydrate and ethylene glycol and dissolving the resultant transparent brittle solid in dry n-propanol. Our thin films with different thickness were prepared by sol-gel method on glass substrates. Optical properties of these films were studied by UV-visible spectrophotometer at 200-800 nm wavelength. The extinction coefficient and band gap were calculated from the transmission spectrum. The analyses show that with the increase of film thickness, both the ultraviolet emission intensity is improved. However, the transmittance in the visible range is hardly influenced by the film thickness, and the averages are all above 80%.