Optical nanocrystallography with tip-enhanced phonon Raman spectroscopy

Department of Chemistry and Department of Physics, University of Washington, Seattle, WA 98195, USA.
Nature Nanotechnology (Impact Factor: 34.05). 09/2009; 4(8):496-9. DOI: 10.1038/nnano.2009.190
Source: PubMed


Conventional phonon Raman spectroscopy is a powerful experimental technique for the study of crystalline solids that allows crystallography, phase and domain identification on length scales down to approximately 1 microm. Here we demonstrate the extension of tip-enhanced Raman spectroscopy to optical crystallography on the nanoscale by identifying intrinsic ferroelectric domains of individual BaTiO(3) nanocrystals through selective probing of different transverse optical phonon modes in the system. The technique is generally applicable for most crystal classes, and for example, structural inhomogeneities, phase transitions, ferroic order and related finite-size effects occurring on nanometre length scales can be studied with simultaneous symmetry selectivity, nanoscale sensitivity and chemical specificity.

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    • "Our group proposed a phenomenological model to account for the polarization dependence of the TERS signal from crystalline silicon based on the introduction of the concept of tip amplification tensor [20]. Recently, this formalism has been adopted to spatially resolve ferroelectric domains in individual BaTiO3 nanocrystals, introducing the concept of a nanocrystollography based on near-field Raman selection rules [21]. Clearly, it would be interesting to extend the application fields of TERS to thin organic layers whenever these exhibit, at least locally, an ordered, crystalline-like structure. "
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