Study of structural, optical and electrical properties of gamma irradiated In₂O₃ thin films for device applications

Abstract

The influence of gamma irradiation on the structural, optical and electrical properties of indium oxide ($\hbox {In}_2\hbox {O}_3$) thin films prepared by thermal evaporation has been reported. The X-ray diffraction analysis revealed that the gamma irradiated films up to a dose of 75 Gy exhibit better crystallinity, with a strong increase in the intensity of peak related to (222) plane of the cubic indium oxide structure. Further increase of the gamma dose results in the reduction of crystallinity and grain size. However, the dislocation density and micro strain show the reverse trend of the dose dependence. The transmittance of the films decreases with the gamma dose up to the same level, resulting in a decrease of bandgap from 3.65 to 3.30 eV. The increase of the band gap at higher doses might be due to increased structural disorder and more defect creation than annihilation. The I–V characteristics measured after each exposed dose showed a decrement in the resistance with the rise in radiation dose up to the same level and exceeding this level leads to damage of the device. This study also suggests that the gamma irradiation can be considered as a tool for the enhancement of the device properties amongst the other applications.