A study of the influence exerted by structural defects on photoluminescence spectra in $n$-3$C$-SiC

Photoluminescence (PL) spectra have been studied in 3$C$-SiC/4$H$-SiC heterostructures and 3$C$-SiC single crystals. It was shown that epitaxial 3$C$-SiC layers grown on 4$H$-SiC substrates have a markedly poorer crystal perfection than do 3$C$-SiC single crystals. It was found that doping with aluminum gives rise to a characteristic PL both in epitaxial layers and in 3$C$-SiC single crystals. At the same time, the electron irradiation of epitaxial layers does not give rise to defect-related PL, in contrast to what is observed for single crystals. An assumption is made that the twin boundaries existing in epitaxial 3$C$-SiC layers can serve as getters of radiation defects that are components of donor–acceptor pairs responsible for the “defect-related” PL.