Highly sensitive gas sensor based on integrated titania nanosponge arrays

Highly sensitive gas sensors were fabricated using nanostructured titania pad arrays. Nanostructured titania (NST) formed is sponge-like consisting of interconnected nanoscale wires and walls, which are made up of anatase nanocrystals. Electrical characterization indicates that contacts were ohmic and NST was highly sensitive to O-2. Variations of hundreds of oxygen molecules over a 20 mu m NST square pad sensing element were detected at 250 degrees C. The NST-based sensor operates at lower temperatures, has fast response time, and superior sensitivity relative to oxygen sensors based on porous undoped titania reported in the literature.