TiO 2 nanotube-based field effect transistors and their application as humidity sensors

Abstract

TiO 2 nanotubes are the building units of various devices of energy- and environment-related applications and the property studies of individual TiO 2 nanotubes are important to understand and improve the performance of TiO 2 nanotubes-based devices. Here we report the electrical property study of individual TiO 2 nanotubes enabled by the construction of field effect transistors based on individual TiO 2 nanotubes. It is found that individual TiO 2 nanotubes exhibit typical n-type electrical conduction characteristics, with electron mobility of 6.9 × 10 −3 cm 2/V s at V ds = 1 V, and electron concentration of 2.8 × 10 17 cm −3. Moreover, the on–off ratio of the TiO 2 nanotube-based field effect transistors is as high as 10 3. Humidity sensing test shows the sensitive response of the individual TiO 2 nanotubes to water vapor.