RISE Microscopy is a novel correlative microscopy technique that combines confocal Raman Imaging and Scanning Electron (RISE) microscopy within one microscope system (Fig. 1a). This unique combination provides distinct advantages with regard to comprehensive sample characterization: electron microscopy is an excellent technique for visualizing surface structures in the nanometer range and confocal Raman imaging is an established method for detection of the chemical and molecular components of a sample with diffraction-limited resolution. In contrast to conventional systems in which individual Raman spectra are collected from areas several micrometers across, RISE can produce diffraction-limited confocal Raman images from the same sub-micron areas investigated by SEM. It can also generate 3D-images and depth profiles to visualize the distribution of the molecular compounds within a sample volume. Both analytical methods are fully integrated into the RISE microscope. Between measurements a precise translation stage automatically transfers the sample inside the microscope’s vacuum chamber and re-positions it. The RISE software carries out the required parameter adjustments and instrument alignments. The acquired results can then be correlated and the Raman and SEM images overlaid.

The instrument itself as well as example measurements demonstrating the potential of its hybrid approach will be presented. An example of correlative Raman and SEM imaging is presented in Figure 1b-d, showing the distribution of TiO2 nanoparticles. Fig. 1b shows the SEM image of TiO2, revealing nanoparticles of two different sizes. From the same sample area an array of 150 x 150 complete Raman spectra was acquired with an integration time per spectrum of 37 ms. From this array two distinct spectra were evaluated as shown in Fig. 1c. They show the two polymorphic phases of TiO2: rutile and anatase. The correlative Raman-SEM image (Fig. 1d) reveals that the large particles correspond to the rutile phase of TiO2, whereas the small particles consist of anatase TiO2, enabling the fine crystallographic structure of the nanoparticles to be differentiated.

Figures:

Figure 1. RISE microscope (a), SEM image of TiO2 nanoparticles (b), Raman spectra of rutile and anatase TiO2 (c), and correlative Raman-SEM image (d).

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EMC Abstracts - https://emc-proceedings.com/abstract/rise-microscopy-correlative-raman-and-sem-imaging/