We have performed electrical and optical measurements to characterize the processes of radiative recombination of carriers for 4H-SiC p-n + junctions. We have detected three levels in the band gap, using capacitance and current deep-level transient spectroscopy, which are responsible for the bands observed in the electroluminescence spectra. We assume that the HK 1 center with activation energy of E v + 0.229 eV and a hole capture cross-section of 8 10 - 1 3 ( (300T) 3 is related to the Al acceptor level.