Alivov Yahya, Funke Hans H, Singh Vivek, Nagpal Prashant
Department of Chemical and Biological Engineering, ‡Materials Science and Engineering, and §Renewable and Sustainable Energy Institute, University of Colorado , Boulder, Colorado, United States.
ACS Appl Mater Interfaces. 2015 Feb 4;7(4):2153-9. doi: 10.1021/am5076666. Epub 2015 Jan 22.
Metal-oxide nanotubes provide large surface areas and functionalizable surfaces for a variety of optical and electronic applications. Here we report air-tunable rectifying behavior, depletion width modulation, and two-dimensional (2D) charge conduction in hollow titanium-dioxide nanotubes. The metal contact forms a Schottky-diode in the nanotubes, and the rectification factor (on/off ratio) can be varied by more than 3 orders of magnitude (1-2 × 10(3)) as the air pressure is increased from 2 mTorr to atmospheric pressure. This behavior is explained using a change in depletion width of these thin nanotubes by adsorption of water vapor on both surfaces of a hollow nanotube, and the resulting formation of a metal-insulator-semiconductor (MIS) junction, which controls the 2D charge conduction properties in thin oxide nanotubes.
