Concentration Effect of Mixed SnO2-ZnO on TiO2 Optical Properties Thin Films prepared by Chemical Spray Pyrolysis Technique

Abstract

In this work, the concentration effect of mixed tin dioxide and zinc oxide on optical properties of titanium dioxide thin films was studied. Thin films were prepared by using spray chemical pyrolysis technique on glass substrate at 350 ͦC. The optical results revealed a weak optical transmittance for Un-doped TiO2 at the end of ultraviolet spectrum followed by an increase, more than 48%, at the near IR spectrum. TiO2 thin films revealed more transparent with blue shift in the absorption edge when the SnO2-ZnO mixed increased. A significant decrease in the absorption coefficient with increasing the mixed of SnO2-ZnO. According to the results of the electronic transition of TiO2, thin films have direct and indirect energy gap, about 3.2 eV and 2.11 eV, respectively. An increase in both types of energy gap was observed with the mixing concentrations of SnO2-ZnO increase. In addition, a significant decrease also was in the refractive index and extinction coefficient with the increasing SnO2-ZnO concentration.