Vertically aligned ZnO nanotube fabricated on an indium tin oxide substrate is found to exhibit strong persistent photoconductivity (PPC). Excitation wavelength-dependent conductance measurement on individual ZnO nanotube reveals the presence of defect states at 240 meV above the valence band edge, which are directly associated with the PPC effect. Our observations are consistent with the hypothesis that double ionization of defect-localized states is responsible for the PPC effect.
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© 2009 American Institute of Physics.
2009
American Institute of Physics
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