It was noted that the epitaxial carbide was likely to contain H and vacancies and that, therefore, V + nH complexes were likely to affect its properties. By using ab initio calculations, it was shown that neutral and positive H atoms were trapped by C vacancies in 3-centre bonds with two Si neighbours. The double-positive charge state of VC + H was not stable in equilibrium and, in the triply-positive state, H bonded to only one of the Si neighbours. Two H atoms, at most, could be accommodated by a single VC. The VC + nH complexes had a donor character and exhibited rather atypical vibration modes for Si-H bonds.

Over-Coordinated Hydrogens in the Carbon Vacancy: Donor Centers of SiC. A.Gali, B.Aradi, P.Deák, W.J.Choyke, N.T.Son: Physical Review Letters, 2000, 84[21], 4926-9