New method for gas identification using a single semiconductor sensor

Simultaneous measurements of changes in semiconductor resistance ΔR and in sensor temperature ΔT gave a new method for gas identification using a single SnO2-based gas sensor. Gas species with any concentration was represented by a point on a particular curve Fi, which was characteristic of a certain species i, on the two-dimensional space (ΔR, ΔT). Thus, the species could be identified as j without uncertainty from a measured point (ΔRm, ΔTm) on the characteristic curve Fj. We identified gas species of H2 (10–1000 ppm), CO (10–500 ppm), C2H5OH (10–5000 ppm) and alkane such as CH4 (10 ppm–2%), C3H8 (10–2000 ppm) and i-C4H10 (10–1000 ppm), and also discriminated volatile organic compounds of C6H6, C6H5CH3 and C6H4(CH3)2 ranging from 2 to 200 ppm.