AUGER AND COULOMB CHARGING EFFECTS IN SEMICONDUCTOR NANOCRYSTALLITES

Theoretical and experimental results are presented providing evidence for fast Anger recombination in silicon nanocrystallites. Calculations give nonradiative lifetimes in the 1 ns range. Luminescence experimen ts on porous silicon exhibit a saturation at high excitation power. Th e Anger effect gives a natural explanation for this saturation as well as for the recently observed quenching of the photoluminescence and v oltage tunable electroluminescence. In this last case the importance o f Coulomb charging effects is shown to be at the origin of the linewid th. The consequences of such fast Auger recombination for the optical efficiency of indirect band-gap semiconductor nanocrystallites are dis cussed.