Abstract
The band Raman intensity is calculated for armchair edged graphene nanoribbons using an extended tight-binding method in which the effect of interactions up to the seventh nearest neighbor is taken into account. The possibility of a double resonance Raman process with multiple scattering events is considered by calculating a matrix through a direct diagonalization of the nanoribbon Hamiltonian. We show that long-range interactions play an important role in the evaluation of both the band intensity and that the main effect of multiple scattering events on the calculated band is an overall increase in intensity by a factor of 4. The band intensity is shown to be independent of the nanoribbon widths for widths larger than 17 nm, leading to the well-known linear dependence of the ratio on the inverse of the crystalline size. The band intensity was shown to be nearly independent of the laser excitation energy and to have a maximum value for incident and scattering photons polarized along the direction of the edge.
- Received 22 March 2011
DOI:https://doi.org/10.1103/PhysRevB.83.245435
©2011 American Physical Society