By using first-principles calculations, the vibronic properties of H in a Si vacancy (VSi+H) were investigated in 3C-SiC. The calculations showed that the neutral VSi+H complex, which could bind an exciton, was stable only in lightly p-type SiC. This result was consistent with experimental findings. The calculations were able to account well for the observed anharmonicity of C–H stretching vibrations up to the third harmonic, and for isotope effects.

Anharmonicity of the C–H Stretch Mode in SiC - Unambiguous Identification of Hydrogen–Silicon Vacancy Defect. A.Gali, B.Aradi, D.Heringer, W.J.Choyke, R.P.Devaty, S.Bai: Applied Physics Letters, 2002, 80[2], 237-9