Neutral aluminum and gallium four particle complexes in silicon carbide polytypes

Optical studies provide a great amount of information about accepters in Si C. The optical recombination of neutral acceptor four particle (bound excit on) complexes has been observed in 4H, 6H, 15R and 3C SIC for Al; 4H, 6H an d 3C SIC for Ga; and in 4H SiC for the shallow B acceptor. A model for the electronic structure of neutral acceptor four particle complexes based on s ymmetry provides a description of the no-phonon spectra for Al and Ga, when the possibility of lattice strain is included. This model is consistent wi th the numbers of no-phonon lines observed for Al and Ga in 3C, 4H and 6H S IG, but there are too many no-phonon lines for Al in 15R SiC. The model is further developed and applied to Zeeman spectra of Al and Ga four particle complexes in 6H SIG, providing further insight into their electronic struct ure. (C) 1999 Elsevier Science S.A. All rights reserved.