Electronic and optical properties of armchair silicon carbide nanotubes from first principles

We calculate the electronic band gap and optical spectra of armchair (n, n) silicon carbide nanotubes (n = 9-12) using density functional theory (DFT) combined with Non equilibrium Green's function (NEGF) method as implemented in the SIESTA code. Our simulation suggests that the armchair SiCNTs are indirect-gap semiconductors and SiCNTs (11, 11) have the largest electronic band gap. The z component of the refractive index of SiCNTs (9, 9) reaches its zenith at energies below 2.5 eV. Moreover, the optical absorption takes place in the energy range similar to 2-5 eV for the z polarization. The simulated armchair SiCNTs with larger diameter have the smaller first optical band gap as well.

Automated summary

The electronic band gap and optical spectra of armchair silicon carbide nanotubes were studied using DFT and NEGF methods, with SiCNTs (11, 11) found to have the largest band gap. The refractive index of SiCNTs (9, 9) peaked at energies below 2.5 eV, with optical absorption occurring in the 2-5 eV range for z polarization. Additionally, SiCNTs with larger diameters exhibited smaller first optical band gaps.