Fabrication of TiO2 Nanotube Arrays and Their Application to a Gas Sensor.

To improve sensing performance, the metal oxide semiconductor (MOS) gas sensor needs to have amuch bigger specific surface area in the active layer, lower power and higher sensitivity. TiO2 nanotube arrays were used for the active layer of a MOS gas sensor because they are chemically stable and electrically semi conductive. To obtain clean, open window nanotubes, two-step anodic oxidation was conducted. The diameter of the window and length of the nanotubes were 60 nm and 5.5 μm, respectively. TiO2 nanotube arrays were transplanted by the SnO2 adhesion layer. The SnO2 adhesion layer had a nanoparticle diameter of 30 nm and a thickness of 4 μm. The sensitivity increased with the CO gas concentration and was 0.061 at 300 ppm. The response was very quick. A power consumption of 80 mW was measured with an effective gas detection performance.