NO₂ Gas Sensing Properties of Electrophoretically Deposited SmFeO₃ Films on an Au Comb-type Microelectrode

Abstract

SmFeO3 semiconductor thin film was formed on a Au comb-type microelectrode by using the EPD method and examined on its sensing property to NO2 gas. The SmFeO3 particles were prepared with the thermal decomposition of Sm[Fe(CN)6] · 4H2O complex at 500 and 900 °C. The EPD was performed in a liquid-droplet of the organic suspension containing the SmFeO3 particles. The EPD films formed on the micro comb-electrode were sintered at 400, 500 and 600 °C. The sensing property to NO2 was fairly affected not only by the decomposition temperature of the complex but also the sintering temperature of the EPD films. The films with the powder decomposed at 500 °C exhibited higher performance than those prepared at 900 °C. Sintering the film at 600 °C exhibited highest sensitivity to 10 ppm NO2 with S = 96 and good response and recovery behaviors were observed even at low temperature at 250 °C. Significant sensitivity was also obtained in 1 and 0.2 ppm NO2.