Spin-polarized ab initio calculations were used to determine the energy differences between the ground and excited states of Si and C vacancies in 3C- and 4H-type material. The calculated transition energies were compared with recent photoluminescence and magnetic resonance data. The calculations were based upon density functional theory in the local spin-density approximation, and used super-cells with 216 or 128 atoms. In general, the results confirmed the conclusions of photoluminescence studies of electron-irradiated samples. This was particularly true of the relationship between the photoluminescence lines or bands in 3C-type material and VSi+ with spin S = ½, and VSi0 with S = 1. Photoluminescence lines at 1.35 and 1.44eV in 4H-type material could be related to VSi0 with S = 1. It was noted that attention also had to be paid to VSi2- with S = 1.

Intravacancy Transition Energies in 3C- and 4H-SiC A.Zywietz, J.Furthmüller, F.Bechstedt: Physical Review B, 2000, 61[20], 13655-8