Photoluminescence efficiency of germanium dots self-assembled on oxides

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DOIResolve DOI: http://doi.org/10.1149/05301.0185ecst
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Proceedings titleGraphene, Ge/III-V, and Emerging Materials for Post CMOS Applications 5
Series titleECS Transactions; Volume 53
Conference223rd ECS Meeting, 5th International Symposium on Graphene, Ge/III-V and Emerging Materials For Post-CMOS Applications, May 12-17, 2013, Toronto, ON, Canada
ISSN1938-5862
ISBN9781607683742
Pages185206; # of pages: 22
SubjectAbsolute intensity; Efficiency curves; Energy dependence; Near-infrared bands; Photoluminescence efficiency; Self-assembled Ge quantum dots; Thermal-annealing; Transmission electron; Atomic force microscopy; Germanium; Graphene; Molecular beam epitaxy; Photoluminescence; Size distribution
AbstractSelf-assembled Ge quantum dots were formed by in-situ thermal annealing of a thin amorphous Ge layer deposited by molecular beam epitaxy either on a thin porous TiO2 layer grown on SiO2 on Si(001) or directly on the SiO2 layer itself. For samples with dot diameters ranging from 10 to 35 nm, the dot photoluminescence (PL) appeared primarily as a wide near-infrared band peaked near 800 meV. The peak energy of the PL band reflects the average dot size and its shape depends on the dot size distribution. Using tight binding and effective mass theoretical models, we have analyzed the PL spectrum in terms of the dot size distribution. The observed size distribution determined from transmission electron and atomic force microscopy allowed the determination of the nonlinear increase in the PL efficiency with decreasing dot diameter. Although the absolute intensities of the PL from the samples vary, the calculated efficiency curves are all well fitted by straight lines on a log-log plot, with essentially the same slope for all samples, thereby demonstrating that under the weak confinement regime investigated here there is a universal power-law increase in PL efficiency with decreasing dot size. Knowing this generic PL efficiency, we show that it is possible to evaluate the size distribution of Ge dots from their PL energy dependence.
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LanguageEnglish
AffiliationMeasurement Science and Standards; National Research Council Canada
Peer reviewedYes
NPARC number21270418
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Record identifier8934a368-0a5d-46cb-82c2-f40664ee75a4
Record created2014-02-10
Record modified2016-05-09
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