Photoluminescence and Zeeman-effect measurements of near-infrared luminescence bands in Cr-doped 4H-type and 6H-type material were performed. The photoluminescence spectrum consisted of 2 no-phonon lines at 1.1583 and 1.1898eV in 4H-type material, and of 3 no-phonon lines at 1.1556, 1.1797 and 1.1886eV in 6H-type material. The observed Zeeman splittings and temperature dependences revealed the spin triplet of the ground state and the orbital doublet structure of the excited state of the Cr-related center. All of the triplets had almost isotropic g-values which were close to 2, with trigonal symmetry and small zero-field splitting values. On the other hand, the effective g-values of the excited state of the center were very anisotropic, with g|| ranging from 0.22 to 0.64 and with g = 0 for various no-phonon lines in both polytypes. On the basis of the Zeeman results, the photoluminescence was attributed to the internal transition, 1E(D) → 3A2(F) within the d-shell of a substitutional neutral C4+ in the 3d2 electronic configuration.

Photoluminescence and Zeeman Effect in Chromium-Doped 4H and 6H SiC. N.T.Son, A.Ellison, B.Magnusson, M.F.MacMillan, W.M.Chen, B.Monemar, E.Janzén: Journal of Applied Physics, 1999, 86[8], 4348-53