Gas-sensor properties of SnO2 films implanted with gold and iron ions

SnO2 gas-sensor films were modified by implantation of gold and iron ions. The change in electrical resistivity of the films caused by inflammable gases, H-2, CO, CH4 and C2H5OH, was measured in the temperature range 100-500 degrees C, and compared to non-implanted films. The morphological changes caused by gold and iron ion implantation were also investigated by atomic force microscopy. After ion implantation and annealing at 600 degrees C, the sensitivity to H-2 and CO gas was found to increase, and the dynamic range of the sensitivity to ethanol was improved. The sensitivity to CH4 was low before and after ion implantation. Fe2O3 (3%SnO2) film was also modified by gold ion implantation for comparison.