Sensitivity and low-frequency noises of gas sensors made on nanoscale composite material

We fabricated, by magnetron sputtering technique, thin-film resistive sensor based on nanocomposite In₂O₃^.Ga₂O₃^.SnO₂ (70 : 20 : 10) structure. Gas sensitivity of fabricated sensors has been measured at different working body (WB) temperatures and different concentrations of acting gases (ethanol and acetone). It was established that our elaborated sensor exhibits noticeable sensitivity to ethanol vapors at already WB temperature of 150 ℃. comparative analysis of sensor sensitivity to different concentrations of ethyl alcohol and acetone showed that the sensor has much higher sensitivity to ethanol vapor. It was established that the gas sensitivity of our developed sensors to influence of such gases as isobutane and methane is negligibly low; this means that our sensor is selective. Since the sensor sensitivity depends linearly on concentration of ethanol and acetone vapor (in case of resistive method), it may also be used for determination of concentrations of these gases. We have shown that the noise diagnostics not only allows determining most sensitively the concentrations of gas vapors, but can also characterize changes in energy distribution of surface states. (author)