Optical Absorption of Graphene Nanoribbon in Transverse and Modulated Longitudinal Electric Field

Abstract

In this paper, the electronic and optical properties of graphene nanoribbons at both external transverse and modulated longitudinal electric field have been investigated. The single π-band tight-binding method, with the nearest neighbor interactions, is used to describe the electronic properties of the graphene nanoribbons. The optical properties of graphene nanoribbons are investigated by Fermi Golden rule within Gradient approximation. Our calculation has shown that applying the electric field would modify the energy dispersions, remove the state degeneracy, alter the sub band spacing, change the energy band gap, cause semiconductor–metal transition and change feature of optical absorption spectra. It is shown that the strength and the period of the electric field have important role on determining the properties of the adsorption peaks in the adsorption spectra of GNRs, namely, changing the frequency and the height of the first peak, altering the other peak position and height and even producing new peaks. The theoretically obtained results were in agreement by other reports on wider graphene ribbons.