In this work, the authors have considered the effect of short-term nonthermal action of microwave radiation on the photoluminescent characteristics of SiC/por-SiC/Er 2 O 3 and SiC/por-SiC structures. The analysis of photoluminescence spectra of these structures, which are excited by radiation with an energy lower than the band gap in the 4H-SiC crystalline substrate, has shown that short-term action of microwave radiation leads to redistribution of radiative recombination centers, which is caused by surface states in the por-SiC layer.