UV-enhanced oxygen sensing of zinc oxide nanowires

UV (ultra violet)-enhanced oxygen sensing using ZnO (zinc oxide) nanowires has been successfully demonstrated with improved sensitivity. These single-crystalline nanowires are grown by the VLS (vapor-liquid-solid) process using inductive heating and self-assembled between two MEMS microstructures by the technique of local vapor deposition. Under 365-nm UV illumination, the as-fabricated device shows up to 500% improvement in oxygen sensitivity as compared with sensing data from the same device without using UV light. The transient responses of ZnO nanowires under UV and oxygen environment are also investigated and a photocurrent decay process is observed and characterized. As such, this UV enhancement sensing scheme could be applicable for nanowire-based gas and chemical sensors.