Time resolved PL study of multi bound excitons in 3C SiC

We have studied the emission related to multiple bound exciton complexes (MBEC) in 3C SiC, using time resolved photoluminescence spectroscopy. In addition to the normal exciton bound to the neutral nitrogen donor, we observe at low temperatures four peaks in the no-phonon spectral region due to the transition of MBECm complexes with up to five (m=5) electron-hole pairs, according to the shell model. The observed emission is due to the recombination of one electron-hole pair in the complex. The time decay of these emissions decreases with increasing m, ranging from 160 ns to 21 ns. For phonon assisted emissions we observe additional splitting of the MBEC due to excited electron states, All emissions within each shell have similar decay times, due to fast relaxation of the electrons inside each shell.