Local density functional calculations were used to investigate models of the center responsible for a prominent set of luminescent lines with zero-phonon lines around3.15eV in H rich 4H-SiC and previously attributed to VSi-H. It was found that the electronic structure of this defect and the character of its vibrational modes were inconsistent with this assignment. In contrast, an H2* center, bound to a C antisite, was more stable than the isolated molecule and possesses a donor level close to that observed for the H-lines. Moreover, its vibrational modes were in good agreement with experiment. A possible mechanism for the radiation enhanced quenching of the defect was proposed.

Hydrogen-Related Photoluminescent Centers in SiC. D.Prezzi, T.A.G.Eberlein, R.Jones, B.Hourahine, P.R.Briddon, S.Öberg: Physical Review B, 2004, 70[20], 205207 (5pp)