Optical spectra of zigzag graphene nanoribbons: a first-principles study

The electrical and optical properties of zigzag graphene nanoribbons is simulated using Density Functional Theory (DFT). It is found that n-ZGNRs (n = 18, 22, 26, 30) have metallic behavior. The results reveal that when the nanoribbon width increases, the first optical bandgap and optical absorption peaks diminish. Furthermore, at energies greater than around 1.40 eV, n-ZGNRs (n = 18, 22, 26, 30) have a negative refractive index for the z polarization. The maximum optical reflection peaks of n-ZGNRs (n = 18, 22, 26, 30) occur at about 5 eV for y polarization. Furthermore, unlike the y polarization, the z components of optical reflectivity are positioned at lower energies. The results show that the optical extinction of the simulated ZGNRs increases with ribbon width. The main reason is that the larger supercells have a higher mass density. For E-y similar to 0-4.50 eV, n-ZGNRs (n = 18, 22, 26, 30) support the conditions for the transverse-electric (TE) mode. Additionally, for Ey

Automated summary

The electrical and optical properties of zigzag graphene nanoribbons were simulated using DFT. The study found that the nanoribbons exhibit metallic behavior and have reduced optical bandgap and absorption peaks as their width increases. Additionally, the nanoribbons show negative refractive index for z polarization and maximum optical reflection peaks at around 5 eV for y polarization.