Micro-scaled hydrogen gas sensors with patterned anodic titanium oxide nanotube film

We have fabricated gas sensors with micro-scale-patterned anodic titanium oxide nanotube films formed by local anodization of titanium wires using a hybrid process between top-down (photolithography) and bottom-up (anodization) processes. We examine the response characteristics of the sensors for hydrogen gas to demonstrate that a few % of hydrogen gas in nitrogen ambient produces currents in the range of mA without special interdigitated electrodes. The sensitivity is remarkably improved by thinning the tube walls. The hybrid process is a suitable method for fabrication of micro-scaled gas sensors, which has useful features such as low power consumption, high reliability and portability.