First principles many-body calculations of electronic structure and optical properties of SiC nanoribbons

Abstract

A first principles many-body approach is employed to calculate the band structure and optical response of nanometer sized ribbons of SiC. Many-body effects are incorporated using the GW approximation, and excitonic effects are included using the Bethe-Salpeter equation. Both unpassivated and hydrogen passivated armchair SiC nanoribbons are studied. As a consequence of low dimensionality, large quasiparticle corrections are seen to the Kohn-Sham energy gaps. In both cases quasiparticle band gaps are increased by up to 2 eV, as compared to their Kohn-Sham energy values. Inclusion of electron-hole interactions modifies the absorption spectra significantly, giving rise to strongly bound excitonic peaks in these systems.The results suggest that hydrogen-passivated armchair SiC nanoribbons have the potential to be used in optoelectronic devices operating in the UV-Vis region of the spectrum. We also compute the formation energies of these nanoribbons as a function of their widths, and conclude that hydrogen-saturated ribbons will be much more stable as compared to the bare ones.

18 pages, 7 figures (included)

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• Planar buckling controlled optical conductivity of SiC monolayer from Deep-UV to visible light region: A first-principles study
• A first-principles study of the electronic, vibrational, and optical properties of planar SiC quantum dots
• Tunable electronic properties of partially edge-hydrogenated armchair boron-nitrogen-carbon nanoribbons