Changes of the absorption cross section of Si nanocrystals with temperature and distance
Result description
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.
Keywords
absorption cross sectionaverage lifetimenanocrystal distancephotoluminescence decaysilicon nanocrystals
The result's identifiers
Result code in IS VaVaI
Alternative codes found
RIV/00216208:11320/17:10367382
Result on the web
DOI - Digital Object Identifier
Alternative languages
Result language
angličtina
Original language name
Changes of the absorption cross section of Si nanocrystals with temperature and distance
Original language description
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.
Czech name
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Czech description
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Classification
Type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
GC16-09745J: Understanding the Luminescence Efficiency of Silicon Quantum Dots
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Beilstein Journal of Nanotechnology
ISSN
2190-4286
e-ISSN
—
Volume of the periodical
8
Issue of the periodical within the volume
Nov 6
Country of publishing house
DE - GERMANY
Number of pages
9
Pages from-to
2315-2323
UT code for WoS article
000415308200001
EID of the result in the Scopus database
2-s2.0-85034224472
Basic information
Result type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
OECD FORD
Physical chemistry
Year of implementation
2017