Size-dependent Raman red shifts of semiconductor nanocrystals.
Size-dependent Raman red shifts of semiconductor nanocrystals.
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DOI：
10.1021/jp804621v
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发表时间：
2008-10
期刊：
影响因子：
--
通讯作者：
C. Yang;Sean Li
中科院分区：
文献类型：
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作者：
C. Yang;Sean Li
通过考虑与原子热振动相关的尺寸相关的均方根平均振幅，研究了尺寸对低维半导体纳米晶体中拉曼红移的影响。将拉曼红移计算结果与Si、InP、CdSe、cds0.65、se0.35、ZnO、CeO2和SnO2纳米晶体的实验数据进行匹配，得到了振动频率的下限。结果表明：(1)窄禁带和宽禁带半导体的拉曼频率随纳米晶体尺寸的减小而减小；(2)晶体尺寸对纳米粒子拉曼频率的影响比纳米线和薄膜的影响更明显；(3)喇曼红移归因于尺寸诱导的声子约束效应和表面弛豫。该模型可能为了解拉曼红移背后的基本机制提供新的见解。
The size effects on Raman red shifts in low-dimensional semiconductor nanocrystals are investigated by considering the size-dependent root-mean-square average amplitude associated with the thermal vibration of atoms. The lower limit of vibrational frequency was obtained by matching the calculation results of Raman red shifts with the experimental data of Si, InP, CdSe, CdS0.65Se0.35, ZnO, CeO2, as well as SnO2 nanocrystals. The results indicate the following: (1) the Raman frequency decreases as the nanocrystal size decreases in both narrow and wide bandgap semiconductors; (2) the influence of crystal size on the Raman frequency of nanoparticles is more pronounced than that of nanowires and thin films; and (3) the Raman red shift is ascribed to the size-induced phonon confinement effect and surface relaxation. This model may provide new insights into the fundamental understanding of the underlying mechanism behind the Raman red shifts.