Effects of nanocrystal shape and size on the temperature sensitivity in Raman thermometry
Date of this Version
8-19-2013Abstract
The effects of CdSe nanocrystal (NC) shape and size on the temperature sensitivity of the Raman shift have been investigated, for the interest of Raman thermometry using NCs. For spherical CdSe NCs of diameters 2.8 nm, 3.6 nm, and 4.4 nm, the temperature sensitivities are -0.0131 cm(-1)/K, -0.0171 cm(-1)/K, and -0.0242 cm(-1)/K, respectively. This trend indicates that as the diameter increases, the effect of increasing phonon anharmonicity dominates over the effect of the decreasing thermal expansion coefficient. On the other hand, triangular NCs with a size of 4.2 nm and elongated NCs of a dimension of 4.6 nm by 14 nm show temperature sensitivities of -0.0182 cm(-1)/K and -0.0176 cm(-1)/K, respectively. This trend indicates that in non-spherical shape NCs, the effect of decreasing thermal expansion coefficient dominates over the effect of slightly increasing phonon anharmonicity. The selection of NCs for Raman thermometry should depend on the specific requirements of temperature sensitivity, spatial resolution, and response time. (C) 2013 AIP Publishing LLC.
Discipline(s)
Nanoscience and Nanotechnology
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Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys. Lett. 103, 083107 (2013); and may be found at http://scitation.aip.org/content/aip/journal/apl/103/8/10.1063/1.4819170. The following article has been submitted to/accepted by Applied Physics Letters. Copyright 2013 Liangliang Chen, Kelly Rickey, Qing Zhao1, Christopher Robinson and Xiulin Ruan. This article is distributed under a Creative Commons Attribution 3.0 Unported License.