Thin films of In_2O_3/SiO as optical gamma radiation sensors

摘要

This paper explores the use of mixed oxide materials such as In_2O_3 and SiO with various compositions in the form of thermally deposited thin films for gamma radiation dosimetry application. ~(137)Cs radiation source with an activity of 370 kBq was used for exposing the samples to γ-radiation. The absorption spectra for as-deposited and y-irradiated films were recorded using CARY 1E UV-Visible Spectrophotometer. The values of the optical band gap E_(opt) were obtained in the view of the Mott and Davis' theory. It was found that the optical properties of thin films were highly affected by composition and manufacturing conditions. For comparison, E_(opt) of as-deposited thin film with composition 75 wt.% of In_2O_3 and 25 wt.% of SiO was found to be 0.9 eV, whereas films with 50 wt.% of In_2O_3 and 50 wt.% of SiO have E_(opt)=1.15 eV, in all cases assuming indirect allowed transition. It was noted that E_(opt) decreased with the increase in radiation dose, i.e. the overall disorder of the system has increased. Thin films of In_2O_3 and SiO mixtures might be regarded as a cost-effective alternative to the existing commercially available radiation detectors.