(Invited) Fast and slow light-emitting silicon-germanium nanostructures

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DOIResolve DOI: http://doi.org/10.1149/05304.0003ecst
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Proceedings titleNanocrystal Embedded Dielectrics for Electronic and Photonic Devices
Series titleECS Transactions; Volume 53
Conference223rd ECS Meeting, Nanocrystal Embedded Dielectrics for Electronic and Photonic Devices, May 12-16, 2013, Toronto, ON, Canada
Pages316; # of pages: 14
SubjectCarrier recombination; Electron-hole droplets; Excitation intensity; Ge concentrations; Hetero interfaces; Light emitting devices; Linear dependence; SiGe quantum wells; Nanocrystals; Photonic devices; Semiconductor quantum wells; Silicon alloys; Three dimensional; Germanium
AbstractEpitaxially-grown three-dimensional Si/SiGe nanostructures (NSs) produce photoluminescence (PL) and electroluminescence in the desired spectral range of 1.3-1.6 μm. We show that by controlling and modifying such Ge-rich SiGe nanoclusters during growth it is possible to fabricate very fast (PL lifetime <20 ns) and hence more efficient SiGe light-emitting devices. The results presented here demonstrate that in such Si/SiGe 3D NSs with a nominal Ge concentration approaching ∼35% the PL peaked near 0.78 eV strongly depends on the Si/SiGe heterointerface abruptness. In other Si/SiGe NS/quantum-well samples with a Ge concentration approaching ∼40%, we find two PL bands peaked at ∼0.8 eV and ∼0.9 eV at low temperatures. The PL peaked at 0.8 eV rises and decays slowly, and it quickly saturates as the excitation intensity increases. In contrast, the PL peaked at 0.9 eV shows a much shorter lifetime and exhibits a linear dependence versus excitation intensity. The slow/delayed PL at 0.8 eV is attributed to carrier recombination at the SiGe NS/Si transition layer while the faster and more efficient PL at 0.9 eV is associated with SiGe quantum wells. More complicated and similarly fast (∼10-7 s) decays are observed at very high excitation intensities due to electron-hole droplet formation. The physics of carrier recombination in these Si/SiGe NSs is discussed.
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AffiliationMeasurement Science and Standards; Information and Communication Technologies; National Research Council Canada
Peer reviewedYes
NPARC number21270417
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Record identifierc4579eca-6ea0-4023-a30b-b332292e497a
Record created2014-02-10
Record modified2016-05-09
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