Gamma radiation and ozone sensing properties of In2O3:ZnO:SnO2 thin films

This work explores the radiation and ozone sensing properties of mixed oxides in the form of thin films. External effects, such as radiation and ozone, cause defects in the materials it interacts with and, consequently, it causes changes in their properties. These changes manifest themselves as the alterations in both the electrical and the optical parameters, which are being measured and employed for dosimetry sensor development. An Edwards E306A thermal coating system was used for In2O3:ZnO:SnO2 (90% : 5% : 5%) films deposition. For the electrical properties measurements, Cu electrodes were manufactured on the glass substrate via thermal evaporation of Cu; then AZ5214 photoresist was spin-coated over it and exposed to UV light via the acetate, containing the desired electrodes patterns. After the exposure, the substrate was placed in Electrolube PDN250ML developer solution and then rinsed in water and placed in the etching solution of SEMO 3207 fine etch crystals to reveal the electrode pattern. The optical properties of In2O3:ZnO:SnO2 thin films were explored using CARY 1E UV-Visible Spectrophotometer. The values of the optical band gap E,p, are estimated in the view of the Mott and Davis' theory. It was noted that E-opt decreases with the increase in radiation dose, i.e. the overall disorder of the system is increased. Doping of In2O3 with 5% ZnO and 5% SnO2 dramatically changes the overall structure of the film. and thus affected its sensing to gamma radiation and ozone. Mixing metal oxides in certain proportions provides a tool for controlling the sensors response.