Nano Archive

The effects of electron-hole separation on the photoconductivity of individual metal oxide nanowires

Prades, J. D. and Hernández-Ramírez, Francisco and Jimenez-Diaz, R and Manzanares, M and Andreu, T and Cirera, A and Romano-Rodriguez, A and Morante, J. R. (2008) The effects of electron-hole separation on the photoconductivity of individual metal oxide nanowires. NANOTECHNOLOGY, 19 (46).

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The responses of individual ZnO nanowires to UV light demonstrate that the persistent photoconductivity (PPC) state is directly related to the electron-hole separation near the surface. Our results demonstrate that the electrical transport in these nanomaterials is influenced by the surface in two different ways. On the one hand, the effective mobility and the density of free carriers are determined by recombination mechanisms assisted by the oxidizing molecules in air. This phenomenon can also be blocked by surface passivation. On the other hand, the surface built-in potential separates the photogenerated electron-hole pairs and accumulates holes at the surface. After illumination, the charge separation makes the electron-hole recombination difficult and originates PPC. This effect is quickly reverted after increasing either the probing current (self-heating by Joule dissipation) or the oxygen content in air (favouring the surface recombination mechanisms). The model for PPC in individual nanowires presented here illustrates the intrinsic potential of metal oxide nanowires to develop optoelectronic devices or optochemical sensors with better and new performances.

Item Type:Article
Subjects:Physical Science > Nanophysics
Analytical Science > Nanotechnology for sensing and actuating
Material Science > Nanochemistry
Material Science > Nanostructured materials
ID Code:1186
Deposited By:Anuj Seth
Deposited On:16 Dec 2008 15:12
Last Modified:31 Mar 2009 17:22

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