Breakdown of the k-conservation rule in quantized Auger recombination in Si1-xGex nanocrystals

Dynamics of quantized Auger recombination in Si1-xGex nanocrystals (NCs) embedded in SiO2 films was studied by femtosecond intraband pump-probe spectroscopy. The temporal change of the electron-hole pair number under strong photoexcitation was well explained by the quantized Auger recombination model that considered the size distribution of NCs. On the basis of the dependence of the Auger decay rate on temperature and Ge composition, we confirmed the occurrence of breakdown of the k-conservation rule in quantized Auger recombination in Si and Si1-xGex NCs.