Ultraviolet Photoresponse of TiO2 Nanotube Arrays Fabricated by Atomic Layer Deposition

Abstract

We used atomic layer deposition with anodic aluminum oxide, to fabricate self-aligned TiO2 nanotube arrays, on a Si substrate, at 400 degrees C. Numerous p-n nanojunctions can be fabricated using this approach. In the absence of the external application of a bias voltage, these crystalline nanotubes make very sensitive ultraviolet sensors. The sensitivity is a result of the built-in voltage, generated by the nanojunction formed between the TiO2 nanotubes and the Si substrate, which separates electron-hole pairs and produces photocurrents. In addition, the one-dimensional structure of the TiO2 nanotubes provides a well-defined path for the transportation of the photo-generated carriers. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3576076] All rights reserved.