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

The adsorption of pyrrole (C₄H₅N) on SiC(111)∕(0001) and SiC(111̄)∕(0001̄) 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 √3×√3 and 3×3 phases of SiC(111̄)∕(0001̄) surfaces are presented and discussed.