Conductance analysis of (Co, Nb, Fe)-doped SnO2 thick film gas sensors

Abstract

Thick films prepared with undoped nanometric SnO 2 particles and with (Co, Nb, Fe)-doped SnO 2 were studied with the purpose of developing oxygen and carbon monoxide gas sensors. The ceramic powders were obtained through the Pechini method. The morphological characteristics were studied with SEM and TEM, after which, they were subjected to sensitivity tests under different atmospheres. A correlation was established between the microstructure of the material, the effects of the additives, and the electrical behavior. The response of the sensor could be explained as the result of the characteristics of the intergranular potential barriers developed at intergrains. It was determined that the SnO 2-doped films have a greater sensitivity between 200 °C and 350 °C.