کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5402690 | 1392739 | 2009 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Random lasing in ZnO nanocrystals
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
Nanocrystalline ZnO powders can act as gain and scattering medium in a random laser where the light emission can be strongly amplified. In this work, we compare the luminescence properties of samples with different particle sizes in the regime of linear and nonlinear optics. In the high-excitation regime random lasing is observed in all samples. Here, the lasing threshold depends strongly on the size distribution in the ensemble. Additional characterization of the samples has been done by determining the absolute quantum efficiency of the radiative processes in the powder. The values are in the 10% range and the near-edge luminescence is strongly influenced by the particle sizes. We show that by annealing the nanocrystals coalesce to larger polycrystalline grains, which results in a new emission band at 3.333Â eV due to the grain boundaries. Furthermore, it is found that in the annealed samples the threshold for random lasing could be considerably decreased.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Luminescence - Volume 129, Issue 12, December 2009, Pages 1685-1688
Journal: Journal of Luminescence - Volume 129, Issue 12, December 2009, Pages 1685-1688
نویسندگان
J. Fallert, R.J.B. Dietz, M. Hauser, F. Stelzl, C. Klingshirn, H. Kalt,