Photoluminescence excitation dependence in three-dimensional Si/SiGe nanostructures

Eun Kyu Lee, Boris V. Kamenev, Theodore I. Kamins, Jean Marc Baribeau, David J. Lockwood, Leonid Tsybeskov

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

Abstract

We find that in SiGe clusters grown on Si using the Stranski-Krastanov (S-K) growth mode, (i) photoluminescence (PL) spectra, (ii) PL lifetime and (iii) PL thermal quench activation energies all exhibit a strong dependence on the excitation intensity. Under PL excitation intensity increasing from 1 to 104 W/cm2, the PL spectra exhibit a blue shift from below the Ge bandgap up to ∼970 meV. The PL lifetime shows a strong dependence on the detection wavelength, decreasing from 20 us at ∼0.8 eV to 200 ns at ∼ 0.9 eV. The process of PL thermal quenching has two clearly distinguished activation energies. At low temperature, a small (∼15 meV) and excitation-independent activation energy is attributed to exciton thermal dissociation. At higher temperature, an excitation-dependent PL thermal quenching activation energy (increasing from ∼ 120 to 340 meV as the excitation intensity increases) is found, and it is attributed to hole redistribution via tunneling and/or thermal ionization over the Si/SiGe valence band energy barrier.

Original languageEnglish (US)
Title of host publicationGroup IV Semiconductor Nanostructures-2006
Pages63-68
Number of pages6
StatePublished - 2007
Event2006 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 27 2006Dec 1 2006

Publication series

NameMaterials Research Society Symposium Proceedings
Volume958
ISSN (Print)0272-9172

Other

Other2006 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period11/27/0612/1/06

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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