Laser-induced fano resonance scattering in silicon nanowires

R. Gupta, Q. Xiong, C. K. Adu, U. J. Kim, P. C. Eklund

Research output: Contribution to journalArticle

153 Scopus citations

Abstract

We have studied the impact of excitation laser power density on the Raman spectrum of small-diameter (5-15 nm) silicon nanowires. At low power densities, a Lorentzian line is observed at 520 cm-1, the same value as that of the zone center LO (TO) phonon in bulk silicon. With increasing laser illumination, the Raman band downshifts and asymmetrically broadens on the low-frequency side. Our results contradict the traditionally accepted notion that a downshifted and asymmetrically broadened line in Si nanowires is due to quantum confinement effects. Rather, we suggest that the downshifting can be due to a laser heating effect of the nanowire and that the asymmetric line shape is due to a Fano interference between scattering from the k = 0 optic phonon and electronic continuum scattering from laser-induced electrons in the conduction band.

Original languageEnglish (US)
Pages (from-to)627-631
Number of pages5
JournalNano letters
Volume3
Issue number5
DOIs
StatePublished - May 1 2003

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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