Photoactive CO gas sensor based on porosity-controlled SnO₂ fabricated by gas-flow thermal evaporation

Abstract

In this study, to compensate for the shortcomings of semiconductor-type gas sen-sors operating at high temperatures, ultraviolet was used to activate and sense the sensors. Ultraviolet rays irradiate the sensing layer, which activates holes/electrons to adsorb oxygen gas in the form of molecules or atoms in ion form and detect the target gas. In addition, the vaporization pressure of thermal evapo-ration was controlled to realize the microstructure of SnO2. Since the target gas reacts on the surface, the reaction area is expanded, and the reaction area is im-proved by expanding the surface area. As a result, it showed a sensitive reactivity to detect 0.1 ppm of carbon monoxide (CO) with only the microstructure SnO2 at room temperature. The sensor was measured by monitoring the change in re-sistance due to the oxidation/reduction reaction by the target gas. In conclusion, through our research, we developed a porous photoactive gas sen-sor that selectively reacts to CO gas.