Recombination statistics and kinetics in semiconductor nanostructures

A new approach to describing the observed features of recombination in semiconductor nanostructures is suggested. In addition to radiative exciton recombination, a nonradiative channel of exciton Auger recombination involving local interface states is taken into account. Recombination statistics and kinetics in semiconductor nanocrystals are considered both for low and high densities of local interface states. The case of a low excitation level, where a statistical approach to recombination in isolated nanocrystals is no longer valid, is analyzed. It is shown that the presence of nonradiative exciton Auger recombination accounts both for the linear dependence of photoluminescence intensity on the excitation level and for the low photoluminescence quantum efficiency.