Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10669709 | Thin Solid Films | 2014 | 5 Pages |
Abstract
Nitrogen-doped graphene thin films were prepared by either chemical vapor deposition (CVD) or electrochemical exfoliation (ECE). Their optical properties were determined in the spectral region of 0.73-6.42Â eV and at temperatures between 200 and 350Â K by spectroscopic ellipsometry. The parameters of the dispersive structures were derived by numerical fitting of the experimental data to the stacked layer model. The optical absorption spectrum of the CVD-grown thin films is characterized by an asymmetric Fano resonance in the ultraviolet frequency region. In contrast, the line shape of the ECE-grown thin films displays less asymmetric. The excitonic resonance of the nitrogen-doped thin films is overall blue shifted by ~Â 0.2-0.3Â eV compared with that of undoped analog. We interpret these results in terms of the exothermic nature of triazine molecule adsorption due to binding to graphene's surface via electron rich nitrogen.
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Authors
C.C. Shen, C.C. Tseng, C.T. Lin, L.J. Li, H.L. Liu,