Radiation-induced changes in thin film structures

Abstract

Optical, electrical and structural properties of metal oxide thin films of tellurium dioxide (TeO2), indium oxide (In2O3) and silicon monoxide (SiO) and their mixtures were studied in terms of gamma radiation influence. These films were prepared using the thermal vacuum evaporation technique. 60Co and 137Cs sources were used to expose the samples to γ-radiation. It was found that the optical band gap values decreased with increasing radiation dose. The radiation induced changes in the electrical properties of these films. Devices with resistor-type structures and p-n junctions were studied. Irradiation resulted in the degradation of the device performance, e.g. current–voltage characteristics of these devices experienced significant alterations. It was observed that values of current were increased with increasing radiation dose. The response of these devices to radiation was found to be composition-dependent. Radiation-induced changes in the structure and surface morphology of In2O3/SiO films were examined by scanning electron microscopy and X-ray diffraction. The irradiation of these thin films with a dose of 8160 μSv led to a change in their phase from amorphous to partially crystallised.