Structural and optical properties of evaporated Zn oxide, Ti oxide and Zn-Ti oxide films

Zn oxide, Ti oxide and Zn-Ti oxide thin films were prepared by vacuum evaporation. Their structural and optical properties have been obtained by X-ray diffractometry (XRD), the energy-dispersive X-ray fluorescence (EDXRF) method and spectrophotometry. The EDXRF method was used to study the stoichiometry of the deposited Zn-Ti oxide films. The XRD patterns show that the prepared ZnO and Zn-Ti oxide films were polycrystalline, while Ti oxide films were amorphous. Spectroscopic optical constants n(lambda) and k(lambda) as well as the energy gap E-g were evaluated from spectrophotometry in the interband transition energy region. It was discovered that ZnO-TiO thin films remain transparent in a shorter wavelength range than the ZnO thin films, resulting from the slight increase of their band gap. It was found that n, k and transmittance values for the mixed-oxide film vary smoothly between the values of the pure constituent oxides in the fundamental energy gap region.