THIN-FILM GAS SENSORS WITH ORGANICALLY MODIFIED SILICATES FOR THE MEASUREMENT OF SO2

Gas sensors based on interdigital capacitors (IDC), with organically modified silicates as a sensitive layer, have been developed for the measurement of SO2 concentrations between 0.5 vpm and some 6000 vpm. The gas-sensitive coating is produced with the sol-gel process and spin-on technique. These sensors are distinguished by good reproducibility and reversibility, a short response time (< 20 s), low cross-sensitivity to other gases, and low dependence on temperature and humidity. The sensor concept, design, manufacture and measurements in a gaseous atmosphere as well as the cross-sensitivity to humidity are discussed.