Carbon dioxide sensitivity of La-doped thick film tin oxide gas sensor

The CO2 sensitivity of a La-doped SnO2 thick film was characterized with variation of the La2O3 content up to 4.5 mol%. Effects of mechanical milling of SnO2 powders on the CO2 sensitivity of a SnO2 thick film sensor were also studied. When exposed to 1000 ppm of CO2, the sensitivity of a SnO2 thick film sensor was improved from 1.14 to 1.52 with increasing the La2O3 doping concentration from 0 mol% to 2.2 mol%. Enhanced sensitivities of 1.45–1.51 were obtained for the thick film sensors processed with mechanically milled SnO2 powders.