Resonant sharp hot free-exciton luminescence in 6H-and 4H-SiC due to inhibited exciton-phonon interaction - art. no. 085203

Experimentally observed sharp luminescence lines from hot free-exciton reco mbination in high-purity 6H- and 4H-SiC are presented. The phenomenon is ex plained in terms of inhibition of the exciton-phonon scattering, prohibited for excitons created resonantly near the bottom of the lowest exciton band at low temperatures. This gives rise to the hot, sharp luminescence. The m odel is in agreement with the observed quenching of the hot luminescence at higher temperatures (>5 K) and in more highly doped samples, as well as wi th the dispersion of the exciton band obtained from the measured electron a nd hole effective masses.