Femtosecond luminescence spectroscopy of core states in silicon nanocrystals

0356926 - FZÚ 2011 RIV US eng J - Journal Article
Žídek, K. - Trojánek, F. - Malý, P. - Ondič, Lukáš - Pelant, Ivan - Dohnalová, Kateřina - Šiller, L. - Little, R. - Horrocks, B.R.
Femtosecond luminescence spectroscopy of core states in silicon nanocrystals.
Optics Express. Roč. 18, č. 24 (2010), s. 25241-25249. ISSN 1094-4087
R&D Projects: GA AV ČR KAN400100701; GA AV ČR(CZ) IAA101120804; GA MŠMT LC510
Institutional research plan: CEZ:AV0Z10100521
Keywords : silicon nanocrystals * ultrafast spectroscopy * photoluminescence spectroscopy
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.749, year: 2010
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-18-24-25241

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.
Permanent Link: http://hdl.handle.net/11104/0195319