Fabrication and H₂-Sensing Properties of SnO₂ Nanosheet Gas Sensors

Vertically formed and well-defined SnO₂ nanosheets are easy to fabricate, involving only a single process that is performed under moderate conditions. In this study, two different sizes of a SnO₂ nanosheet were concurrently formed on a Pt interdigitated electrode chip, with interconnections between the two. As the SnO₂ nanosheets were grown over time, the interconnections became stronger. The ability of the fabricated SnO₂ nanosheets to sense H₂ gas was evaluated in terms of the variation in their resistance. The resistance of a SnO₂ nanosheet decreased with the introduction of H₂ gas and returned to its initial level after the H₂ gas was replaced with air. Also, the response-recovery behaviors were improved as a result of the growth of the SnO₂ nanosheets owing to the presence of many reaction sites and strong interconnections, which may provide multipassages for the electron transfer channel, leading to the acceleration of the reaction between the H₂ gas and SnO₂ nanosheets.