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

TL;DR

This study uses advanced many-body computational methods to analyze the electronic and optical properties of SiC nanoribbons, revealing significant quasiparticle and excitonic effects that influence their potential in optoelectronic applications.

Contribution

It presents the first detailed many-body calculations of SiC nanoribbons, incorporating GW and Bethe-Salpeter methods to reveal their electronic structure and optical responses.

Findings

Quasiparticle band gaps increase by up to 2 eV compared to Kohn-Sham gaps.

Strongly bound excitonic peaks significantly modify absorption spectra.

Hydrogen passivation enhances stability and optoelectronic potential.

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.