Exciton states of silicon nanocrystals studied by magneto-optical spectral hole burning

The absorbing and emitting states of excitons, confined in silicon nanocrystals, are separately investigated by magneto-optical spectral hole burning. Due to Zeeman splitting of the exciton ground level, the whole persistent spectral hole shifts linearly towards lower energies with rising magnetic field. Contrarily, the external magnetic field applied (up to 10 T) does not influence the absorbing state. This strongly supports the excitonic origin of the visible light emission from silicon nanocrystals in porous silicon and the triplet (singlet) nature of the emitting (absorbing) states.