Post-annealing effect of thin platinum oxide film on tin oxide film for an application enhancing gas sensitivity

A thin platinum oxide film was stacked on a tin oxide film, a well-known gas-sensing semiconductor, to improve its gas sensitivity. The response property to ethanol gas was enhanced by about three times by the stacking annealed at 600 °C. Post-annealing, platinum oxide was reduced to platinum and tin oxide was in a polycrystalline state. The results indicate that applying platinum oxide is effective in improving sensitivity when annealing at a high temperature of 600 °C is required for the fabrication of gas sensors.