拉曼光谱
声子
材料科学
纳米颗粒
凝聚态物理
激光线宽
联轴节(管道)
谱线
核磁共振
物理
分析化学(期刊)
纳米技术
量子力学
化学
冶金
色谱法
激光器
作者
Jonathan E. Spanier,Richard D. Robinson,Feng Zhang,Siu‐Wai Chan,Irving P. Herman
出处
期刊:Physical review
日期:2001-11-29
卷期号:64 (24)
被引量:914
标识
DOI:10.1103/physrevb.64.245407
摘要
The combined effects of strain and phonon confinement are seen to explain why the Raman peak near $464{\mathrm{cm}}^{\ensuremath{-}1}$ in ${\mathrm{CeO}}_{2\ensuremath{-}y}$ nanoparticles shifts to progressively lower energies and the lineshape of this feature gets progressively broader and asymmetric (on the low-energy side) as the particle size gets smaller. The increasing lattice constant measured for decreasing particle size explains this Raman shift well. The linewidth change is fairly well explained by the inhomogenous strain broadening associated with the small dispersion in particle size and by phonon confinement. The spectra are also likely to be directly affected by the presence of oxygen vacancies. Comparison of the temperature dependence of the Raman lineshape in the nanoparticles and the bulk shows that phonon coupling is no faster in the nanoparticles, so size-dependent phonon coupling does not contribute to the large nanoparticle peak red shifts and broadening at room temperature. Irreversible thermally induced changes are observed in the Raman peak position of the nanoparticles.
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