Strong anharmonicity and phonon confinement on the lowest-frequency Raman mode of nanocrystalline anatase TiO2

被引：12

作者：

Gao, Kun ^{[1
]}

机构：

[1] Univ Sci & Technol China, Dept Phys, Hefei 230026, Anhui, Peoples R China

来源：

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS | 2007年 / 244卷 / 07期

关键词：

D O I：

10.1002/pssb.200743073

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

We calculated and analyzed the effects of temperature and crystallite size on the Raman properties of nanocrystalline anatase TiO2 by using the related models mentioned previously [Tang and Herman, Phys. Rev. B 43, 2299 (1991); Richter et al., Solid State Commun. 39, 625 (1981)]. The temperature dependence of the Raman spectra of two different crystallite sizes of anatase TiO2 were obtained. Careful measurements of the frequency shifts of Raman modes were carried out at different temperatures. Through fitting the experimental data, pure-volume and the pure-temperature contributions to the frequency shifts of the lowest- and highest-frequency E-g modes, respectively, have been calculated. The results indicated that strongly intrinsic anharmonicity arising from optical-phonon couplings was the origin of hardening upon increasing temperature for the lowest-frequency Raman mode. The phonon-confinement effect on this mode was analyzed and anharmonic shifts of optical phonons with two different kinds of crystallite sizes were also compared. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

引用

页码：2597 / 2604

页数：8

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