Factors Determining the Carbon Monoxide Sensing Properties of Tin Oxide Thick Films Calcined at Different Temperatures

Abstract

Effects of calcinations temperature on the gas-sensing properties of SnO₂ thick films were explored by measuring the variations in resistance with CO concentration. As the calcining temperature increased from 500° to 1100°C, the absolute values of the slopes in the log (concentration)vs log (resistance) curves gradually decreased from −0.9 to −0.2. The data were analyzed with the equations proposed by Madou and Morrison. It was suggested that the reduction in the formation rate of oxygen adsorbates was responsible for the decrease in the absolute slope, and hence a relatively high sensitivity was attained in a low gas concentration with a largely crystallizes sample.