Arrayed Nanostructured Titania Functionalized for Hydrogen Detection

Arrays of nanostructured titania (NST) sensing elements have been fabricated on the wafer scale using standard microfabrication techniques. Sensing elements are 20 µm on a side and formed by the oxidation of titanium thin films in aqueous hydrogen peroxide. NST elements as formed are highly sensitive to oxygen, but only slightly sensitive to hydrogen. Improved sensitivity to hydrogen is achieved by modification of the elements with platinum. A platinum salt solution is introduced to the NST sensor elements and subsequently thermally decomposed. When exposed to 10mT of hydrogen, the functionalized devices exhibit a one order of magnitude resistance decrease with a response time of approximately 4 sec; conversely as grown NST exhibit a resistance increase with a response time of 600 sec under the same conditions. Proposed sensing mechanisms of the NST elements are briefly discussed