Analysis of the sharp donor-acceptor pair luminescence in 4H-SiC doped with nitrogen and aluminum -: art. no. 165211

We analyze the sharp lines in the donor-acceptor (nitrogen-aluminum) emission spectrum in 4H-SiC by means of a fit with theoretically calculated spectra. The theory accounts for the anisotropy and the presence of inequivalent sites in this polytype of SiC, and it is shown that the predominant emission in the linear part of the spectrum is due to pairs involving nitrogen donor and aluminum acceptor at hexagonal sites. The fit allows determination of the ionization energy of the aluminum at hexagonal site, 199+/-2 meV, which is in excellent agreement with the results obtained using free-to-bound spectra.