Raman microanalysis for nano-materials: Bringing Raman spectroscopy to the SEM and AFM microscope and the new SERS imaging techniques
Keywords: Raman instrumentation
Abstract:Advances in Raman instrumentation and the ease of use of modern micro-Raman instruments have allowed Raman microscopy to become a routine method of chemical analysis in an optical microscope. However Raman imaging in an optical microscope had remained a time intensive spectroscopic method, generally not well suited to surveying large areas or nano-materials where there are potentially unknown constituents. The spatial resolution problem has been solved by incorporating Raman spectroscopy into non-optical microscopes, for example scanning electron microscopes and atomic force microscopes. The scanning electron microscope and atomic force microscope support a number of “fast” chemical and topographical contrast methods, including energy dispersive x-ray analysis and cathode luminescence and fluorescence, that can greatly simplify area composition distribution analysis. Additionally Renishaw’s new method of mapping, Streamline™, improves large area mapping problem of speed by utilizing a multiplexed line focus illumination method and fast CCD readout. The multiplex illumination method of Streamline™ mapping is ideal for use with the new generation of SERS substrates. A discussion and comparison of the various imaging techniques will be discussed with Streamline™ mapping examples that highlight the advantages for nano-materials.