title: Femtosecond luminescence spectroscopy of core states in silicon nanocrystals.
abstract: We present a study of ultrafast carrier transfer from highly luminescent states inside the core of silicon nanocrystal (due to quasidirect transitions) to states on the nanocrystal-matrix interface. This transfer leads to a sub-picosecond luminescence decay, which is followed by a slower decay component induced by carrier relaxation to lower interface states. We investigate the luminescence dynamics for two different surface passivation types and we propose a general model describing spectral dependence of ultrafast carrier dynamics. Our results stress the crucial role of the energy distribution of the interface states on surface-related quenching of quasidirect luminescence in silicon nanocrystals. We discuss how to avoid this quenching in order to bring the attractive properties of the quasidirect recombination closer to exploitation.
authors.affiliation: Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague, Czech Republic. zidek@karlov.mff.cuni.cz
authors.forename: K
authors.initials: K
authors.lastname: Žídek
authors.forename: F
authors.initials: F
authors.lastname: Trojánek
authors.forename: P
authors.initials: P
authors.lastname: Malý
authors.forename: L
authors.initials: L
authors.lastname: Ondič
authors.forename: I
authors.initials: I
authors.lastname: Pelant
authors.forename: K
authors.initials: K
authors.lastname: Dohnalová
authors.forename: L
authors.initials: L
authors.lastname: Šiller
authors.forename: R
authors.initials: R
authors.lastname: Little
authors.forename: B R
authors.initials: BR
authors.lastname: Horrocks