Size-dependent evolution of phonon confinement in colloidal Si nanoparticles

Pengfei Zhang*, Yu Feng, Rebecca Anthony, Uwe Kortshagen, Gavin Conibeer, Shujuan Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

A size-dependent evolution of phonon confinement is revealed in Si nanoparticles (NPs) via Raman spectroscopy. By introducing a variable confinement factor, α, into a well-known phenomenological phonon confinement model (PCM) developed by Richter et al., acceptable fits are achieved to downshifted and asymmetrically broadened Raman spectra of Si NPs with different diameters, d, from 2.4 nm to 6.3 nm. A comparative study using Raman spectra of colloidal Si NPs, for the first time, shows an apparent positive linear correlation between α and the Si NP size. Based on the PCM, the amplitude of the atomic vibration (phonon) at the real physical boundary of NPs is proportional to e-α/2, which indicates that the amplitude of the first order optical phonon is relatively larger at the edges for smaller Si nanostructures despite of their stronger phonon confinement weighed by α/d2.

Original languageEnglish
Pages (from-to)1110-1116
Number of pages7
JournalJournal of Raman Spectroscopy
Volume46
Issue number11
DOIs
Publication statusPublished - Nov 2015
Externally publishedYes

Keywords

  • phonon confinement
  • Raman spectroscopy
  • Si nanoparticles

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