NATURE OF SENSITIVITY PROMOTION IN PD-LOADED SNO2 GAS SENSOR

The nature of electronic interaction between noble metal and semicondu cting oxide was investigated for Pd-loaded SnO2 sensor elements. It wa s shown that SnO2 grains contacting to PdO were strongly depleted of e lectrons in air. This electronic interaction disappears on exposure no t only to H-2-containing air but also to He (inert gas). On the basis of these results, it was suggested that the adsorbed oxygen formed at the PdO-SnO2 interface is responsible for the electronic interaction.