Interplay between phonon confinement effect and anharmonicity in silicon nanowires

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Abstract

Getting light out of silicon is a difficult task since the bulk silicon has an indirect energy electronic band gap structure. It is expected that this problem can be circumvented by silicon nanostructuring, since the quantum confinement effect may cause the increase of the silicon band gap and shift the photoluminescence into the visible energy range. The increase in resulting structural disorder also causes the phonon confinement effect, which can be analyzed with a Raman spectroscopy. The large phonon softening and broadening, observed in silicon nanowires, are compared with calculated spectra obtained by taking into account the anharmonicity, which is incorporated through the three and four phonon decay processes into Raman scattering cross-section. This analysis clearly shows that the strong shift and broadening of the Raman peak are dominated by the anharmonic effects originating from the laser heating, while confinement plays a secondary role.

Details

Original languageEnglish
Pages (from-to)109-111
JournalPhysica E: Low-dimensional Systems and Nanostructures
Volume38
Issue number1-2
DOIs
Publication statusPublished - May 2007
EventEuropean Material Society - Nice, France
Duration: 2 Jun 20067 Jun 2006

Keywords

  • nanowires, silicon, Raman spectroscopy

ID: 194655