Clean and pyrrole-functionalized Si- and C-terminated SiC surfaces: First-principles calculations of geometry and energetics compared with LEED and XPS

Abstract

The adsorption of pyrrole $\left({\mathrm{C}}_4{\mathrm{H}}_5\mathrm{N}\right)$ on $\mathrm{Si}\mathrm{C}\left(111\right)∕\left(0001\right)$ and $\mathrm{Si}\mathrm{C}\left(\overline{111}\right)∕\left(000\overline{1}\right)$ surfaces is studied by means of low-energy electron diffraction and x-ray photoelectron spectroscopy. Accompanying first-principles calculations of energies, geometries, and core-level shifts elucidate possible bonding geometries in dependence on the polarity and the reconstruction of the clean SiC surface. Models for the $\sqrt{3}\times \sqrt{3}$ and $3\times 3$ phases of $\mathrm{Si}\mathrm{C}\left(\overline{111}\right)∕\left(000\overline{1}\right)$ surfaces are presented and discussed.