Investigations on the effect of gamma-ray irradiation on the gas sensing properties of SnO2 nanoparticles

In recent years, SnO2 nanoparticles (NPs) have been subjected to various modifications in order to improve their performance in sensing and other applications. Here, we report the synthesis of SnO2. NPs by microwave irradiation, and subsequent exposure to gamma (gamma) radiation at different doses (0-150 kGy) to induce desirable physico-chemical properties. The irradiated samples were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM and HR-TEM), and photoluminescence (PL) to evaluate the effect of gamma-ray irradiation on their morphology and microstructure. The results revealed that the bulk crystal structure remained unchanged after irradiation, while the existence of defects and a damaged over-layer have been confirmed by PL and HR-TEM respectively. The influence of gamma-irradiation on the electrical and CO sensing characteristics was also investigated in the temperature range between 150 and 400 degrees C. gamma-irradiated SnO2 NP based resistive sensors showed better CO sensing characteristics (i.e. higher response and lower working temperature) compared to non-irradiated SnO2. Upon optimizing the.-ray dose irradiation level and working temperature, a ten-fold enhancement in the response to CO has been achieved (R/R-0 = 12 to 50 ppm of CO in air) in 50 kGy irradiated SnO2 NP based sensors operating at 150 degrees C. A possible mechanism for the enhanced sensing performance of.-irradiated SnO2 NPs has been proposed.