Tuesday, June 11, 2013

1306.1594 (Long-Jyun Su et al.)

Creating high density ensembles of nitrogen-vacancy centers in
nitrogen-rich type Ib nanodiamonds
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Long-Jyun Su, Chia-Yi Fang, Yu-Tang Chang, Kuan-Ming Chen, Yueh-Chung Yu, Jui-Hung Hsu, Huan-Cheng Chang
This work explores the possibility of increasing the density of negatively charged nitrogen-vacancy centers [NV-] in nanodiamonds using nitrogen-rich type Ib diamond powders as the starting materials. The nanodiamonds (10 - 100 nm in diameters) were prepared by ball-milling of microdiamonds, in which the density of neutral and automatically dispersed nitrogen atoms [N0] was measured by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). A systematic measurement for the fluorescence intensities and lifetimes of the crushed monocrystalline diamonds as a function of [N0] indicated that the [NV-] increases nearly linearly with [N0] at 100 - 200 ppm. The trend, however, failed to continue for nanodiamonds with higher [N0] (up to 390 ppm) but poorer crystallinity. We attribute the result to a combined effect of fluorescence quenching as well as the lower conversion efficiency of vacancies to NV- due to the presence of more impurities and defects in these as-grown diamond crystallites. The principles and practice of fabricating brighter and smaller fluorescent nanodiamonds (FNDs) are discussed.
View original: http://arxiv.org/abs/1306.1594

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