In situ infrared emission spectroscopic study of the adsorption of H2O and hydrogen-containing gases on Ga2O3 gas sensors

Infrared emission spectroscopy (IRES) was used for studying in situ gas-surface interactions and adsorbed species on Ga2O3 at elevated temperatures used for gas sensors. Regarding the permanent presence of humidity in most gas sensor applications, the interaction of H2O with the sensor surface was observed under working conditions in order to emphasize the benefits of IRES for the understanding of gas sensing mechanisms. The coadsorption of water and H2,C2H4, acetone and ethanol was investigated to point out the role of humidity in the sensitive reactions to organic gases. Screen printed Ga2O3 films were studied in the temperature range from 250°C up to 650°C. These results were correlated with simultaneous conductivity measurements. The evident influence of the addition of water on the surface chemistry of Ga2O3 during the adsorption of hydrogen-containing gases is confirmed by this work.