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Comparative Study of Far-Field and Near-Field Raman Spectra from Silicon-Based Samples and Biological Nanostructures

2011; American Chemical Society; Volume: 115; Issue: 50 Linguagem: Inglês

10.1021/jp206659z

1932-7455

Péter Hermann, Heinz Fabian, Dieter Naumann, Antje Hermelink,

Advanced Fluorescence Microscopy Techniques

Raman spectroscopic characterization of biological nanostructures requires near-field techniques, which provide nanoscale resolution and high sensitivity simultaneously. Tip-enhanced Raman spectroscopy provides the required sensitivity to obtain chemical and structural information from such small structures. However, near-field spectra typically show significant intensity variations and band shifts when comparing the spectroscopic information acquired from sample positions even a few nm apart. In the present study, we compare far-field and near-field Raman spectra of silicon-based samples and biological nanostructures like avipox virus or amyloid fibrils. It is found that the width of the bands in tip-enhanced spectra is typically narrower than in the corresponding far-field spectra. Additionally, the observed spectral variations in near-field Raman spectra are strongly influenced by the structural and chemical heterogeneity of the sample.