Improvement of micromachined SnO2 gas sensors selectivity by optimised dynamic temperature operating mode

This study shows the influence of short temperature variations on the transient response of a nanoparticular SnO2 gas sensor. By consideration of the shape and time constants of the normalized response curves, we can differentiate different gas mixtures at a ppm level. In this paper, different concentrations of CO (from 50 to 200 ppm) are well differentiated even in high level of C3H8 and NO2 concentrations. The shapes of transient responses are also modified by adding different catalysts (Pt, Pd) in SnO2 sensing layer. This new method of analysis is promising to conceive a selective gas detector based on combination of temperature profiles and different sensitive layers.