Gamma radiation-induced changes in the electrical and optical properties of tellurium dioxide thin films

Abstract

Thin films of tellurium dioxide (TeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) were investigated for /spl gamma/-radiation dosimetry purposes. Samples were fabricated using thermal evaporation technique. Thin films of TeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> were exposed to a /sup 60/Co /spl gamma/-radiation source at a dose rate of 6 Gy/min at room temperature. Absorption spectra for TeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> films were recorded and the values of the optical band gap and energies of the localized states for as-deposited and /spl gamma/-irradiated samples were calculated. It was found that the optical band gap values were decreased as the radiation dose was increased. Samples with electrical contacts having a planar structure showed a monotonic increase in the values of current with the increase in radiation dose up to a certain dose level. The observed changes in both the optical and the electrical properties suggest that TeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin film can be considered as an effective material for room temperature real time /spl gamma/-radiation dosimetry.