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Advances in Condensed Matter Physics
Volume 2014 (2014), Article ID 184120, 5 pages
http://dx.doi.org/10.1155/2014/184120
Research Article

Persistent Photoconductivity in ZnO Nanowires in Different Atmospheres

Institute of Solid State Physics, Friedrich Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany

Received 4 December 2013; Accepted 12 January 2014; Published 18 February 2014

Academic Editor: Jianye Li

Copyright © 2014 Davide Cammi and Carsten Ronning. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigated the photoconductivity of single ZnO nanowire device as a function of the surrounding atmosphere, considering the comparison between reduced pressure, inert gas environments, and air. We show that after UV excitation the photocurrent persists for hours, in particular in vacuum, nitrogen, and argon. In the presence of oxygen, the photodecay rate is initially fast but then becomes considerably slower, resulting in a long persisting photo-conductivity tail. Our proposed model explains the persistence of the photoconductivity (PPC) in terms of band bending at the surface of the nanowires, which is related to the trapping of electrons from the conduction band.