Fast and slow light-emitting silicon-germanium nanostructures

D. J. Lockwood, X. Wu, J. M. Baribeau, S. A. Mala, N. Modi, L. Tsybeskov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Epitaxially-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.

Original languageEnglish (US)
Title of host publicationNanocrystal Embedded Dielectrics for Electronic and Photonic Devices
Pages3-16
Number of pages14
Edition4
DOIs
StatePublished - 2013
EventNanocrystal Embedded Dielectrics for Electronic and Photonic Devices - 223rd ECS Meeting - Toronto, ON, Canada
Duration: May 12 2013May 16 2013

Publication series

NameECS Transactions
Number4
Volume53
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

Other

OtherNanocrystal Embedded Dielectrics for Electronic and Photonic Devices - 223rd ECS Meeting
CountryCanada
CityToronto, ON
Period5/12/135/16/13

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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