Abstract:
It has been shown that, at elevated temperatures ($\sim$ 350$^\circ$C), the most distinct response to H$_2$ from the thin film structure Pt/WO$_x$/SiC is achieved at registration of change in voltage for the reverse branch of a current-voltage characteristic. Comparative studies of electric current conduction through the structure and over its surface (with deposited Pt film) have led to the conclusion that a change in properties of the Pt/WO$_x$ and WO$_x$/SiC interfaces under action of H$_2$ mostly determines efficiency of response of the structure in the case of “transverse” measuring geometry. In the case of a 2% concentration of H$_2$ in air the voltage shift for the reverse branch at a current of $\sim$ 10 $\mu$A reached 5 V against 2 V on the forward branch and “planar” geometry of measurements.