9:45 AM - 10:00 AM
[24a-E204-2] Polarity reversal of resistance response to trace H2 gas in the air between asymmetrically shaped electrodes on rutile-TiO2 single crystal
Keywords:semiconductor gas sensor, hydrogen, resistive switching
We investigated the resistance response to trace hydrogen gas in the air between the asymmetrically shaped point contact- (Pt tip) and plane contact- (Al thin-film) electrodes formed in-plane on a rutile TiO2 single crystal at 673 K. It was found that the polarity of the resistance response, that is, the increase or the decrease of the resistance by exposing to hydrogen, reverses depending on the bias voltage polarity. This reversal mechanism of the resistance response was analyzed from the electrical conduction properties, and the depth profile of the oxygen tracer (18O) in the electric field-induced diffusion. The application of this reversal of the resistance response for separating hydrogen and ethanol in the trace gas sensing is discussed, which is quite limited for a conventional semiconductor gas sensor.