First-principles study of confinement effects on the Raman spectra of Si nanocrystals.
Phys Rev Lett
; 105(11): 115504, 2010 Sep 10.
Article
em En
| MEDLINE
| ID: mdl-20867585
ABSTRACT
The Raman spectra of Si nanocrystals are studied as a function of nanocrystal diameter using pseudopotential density functional theory and the Placzek approximation. Our calculations reproduce the redshift and broadening of the optical Raman peak with decreasing nanocrystal size, and calculated peak frequencies show good agreement with experimental values. We also find that a surface induced softening of vibrational modes is largely responsible for the Raman redshift, with relaxation of momentum conservation playing only a minor role.
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Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article