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Changes of the absorption cross section of Si nanocrystals with temperature and distance
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SYSNO ASEP 0482700 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Changes of the absorption cross section of Si nanocrystals with temperature and distance Author(s) Greben, M. (CZ)
Khoroshyy, Petro (UOCHB-X) ORCID, RID
Gutsch, S. (DE)
Hiller, D. (DE)
Zacharias, M. (DE)
Valenta, J. (CZ)Source Title Beilstein Journal of Nanotechnology. - : Beilstein - Institut zur Foerderung der Chemischen Wissenschaften - ISSN 2190-4286
Roč. 8, Nov 6 (2017), s. 2315-2323Number of pages 9 s. Language eng - English Country DE - Germany Keywords absorption cross section ; average lifetime ; nanocrystal distance ; photoluminescence decay ; silicon nanocrystals Subject RIV CF - Physical ; Theoretical Chemistry OECD category Physical chemistry Institutional support UOCHB-X - RVO:61388963 UT WOS 000415308200001 EID SCOPUS 85034224472 DOI 10.3762/bjnano.8.231 Annotation The absorption cross section (ACS) of silicon nanocrystals (Si NCs) in single-layer and multilayer structures with variable thickness of oxide barriers is determined via a photoluminescence (PL) modulation technique that is based on the analysis of excitation intensity-dependent PL kinetics under modulated pumping. We clearly demonstrate that roughly doubling the barrier thickness (from ca. 1 to 2.2 nm) induces a decrease of the ACS by a factor of 1.5. An optimum separation barrier thickness of ca. 1.6 nm is calculated to maximize the PL intensity yield. This large variation of ACS values with barrier thickness is attributed to a modulation of either defect population states or of the efficiency of energy transfer between confined NC layers. An exponential decrease of the ACS with decreasing temperature down to 120 K can be explained by smaller occupation number of phonons and expansion of the band gap of Si NCs at low temperatures. This study clearly shows that the ACS of Si NCs cannot be considered as independent on experimental conditions and sample parameters. Workplace Institute of Organic Chemistry and Biochemistry Contact asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Viktorie Chládková, Tel.: 232 002 434 Year of Publishing 2018 Electronic address https://www.beilstein-journals.org/bjnano/articles/8/231
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