title: Red-shifted carrier multiplication energy threshold and exciton recycling mechanisms in strongly interacting silicon nanocrystals.
abstract: We present density functional theory calculations of carrier multiplication properties in a system of strongly coupled silicon nanocrystals. Our results suggest that nanocrystal-nanocrystal interaction can lead to a reduction of the carrier multiplication energy threshold without altering the carrier multiplication efficiency at high energies, in agreement with experiments. The time evolution of the number of electron-hole pairs generated in a system of strongly interacting nanocrystals upon absorption of high-energy photons is analyzed by solving a system of coupled rate equations, where exciton recycling mechanisms are implemented. We reconsider the role played by Auger recombination which is here accounted also as an active, nondetrimental process.
authors.affiliation: Department of Science and Methods for Engineering (DISMI), University of Modena and Reggio Emilia , via Amendola 2, Pad. Morselli, 42122 Reggio Emilia, Italy.
authors.forename: Ivan
authors.initials: I
authors.lastname: Marri
authors.forename: Marco
authors.initials: M
authors.lastname: Govoni
authors.forename: Stefano
authors.initials: S
authors.lastname: Ossicini