摘要
Time-integrated photoluminescence （PL） spectra between 1.2 and 2.25 eV of ZnO nanoparticles were observed at ambient temperatures when they were excited by a picosecond （ps） laser pulse at a low photon energy of 2.33 eV/532 rim, to show clear red shift when the excitation intensiW increased. Gaussian analysis shows that the red shift is due to increase of the relative magnitudes of the Gaussian combination in the low energy region. Temporal evolution of the dominant emissions exhibited a similar double-exponential decay process, in which the respective two distinct decay durations of 189 ps at the corresponding amplitude of 82% and 2081 ps at 18% were identified. Speculation based on the surfacestate emission due to the large surface-to-volume ratio of nanoscale materials is used to explain the phenomena.
Time-integrated photoluminescence （PL） spectra between 1.2 and 2.25 eV of ZnO nanoparticles were observed at ambient temperatures when they were excited by a picosecond （ps） laser pulse at a low photon energy of 2.33 eV/532 rim, to show clear red shift when the excitation intensiW increased. Gaussian analysis shows that the red shift is due to increase of the relative magnitudes of the Gaussian combination in the low energy region. Temporal evolution of the dominant emissions exhibited a similar double-exponential decay process, in which the respective two distinct decay durations of 189 ps at the corresponding amplitude of 82% and 2081 ps at 18% were identified. Speculation based on the surfacestate emission due to the large surface-to-volume ratio of nanoscale materials is used to explain the phenomena.
基金
supported by the National Natural Science Foundation of China (Grant No.10574165)
the Education Ministry of China,the Science and Technology Department of Guangdong Province,the Education Department of Guangdong Province,and the Science and Technology Department of Guangzhou City(2005A10701004)
