Tunable photoluminescence and photoconductivity in ZnO one-dimensional nanostructures with a second below-gap beam

Tunable photoluminescence (PL) and photoconductivity (PC) with a second below-gap beam were demonstrated on ZnO nanorods and nanoribbons. We found that both PL and PC could be quenched as the second beam was applied to the nanostructures, and this behavior was excluded from thermal effect by comparing the phonon replica spectra with that from heating the sample directly. The most quenching effect occurred near the defect transition located at 520 nm. The underlying mechanism of the quenching behavior was attributed to the defect transition between different states of oxygen vacancies. Size-dependence measurement lets us know that the effect occurs near the surface of nanostructures, and the power-dependent measurement further confirms the underlying mechanism we proposed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3590152]