Patterned carbon nanotube assemblies with bent nanotube bundles were investigated with combined atomic force microscopy and confocal Raman imaging spectroscopy to identify conditions of carbon nanotubes in the bent state. We showed that the tangential G mode on Raman spectra systematically shifts downward upon nanotube bending as was predicted earlier. This lower frequency shift is attributed to the tensile stress, which results in the loosening of C–C bonds in the outer nanotube walls.

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Confocal Raman microscopy was applied in order to investigate the homogeneity of donor doping in Nb:SrTiO3 single crystals. Measurements of local Raman spectra revealed a systematic relation between the intensity of the Raman signal and the donor content of the crystals. We successfully elaborated a correspondence between the electronic structure and the intensity of the Raman lines using a crystal with macroscopic inhomogeneity as a demonstration sample. By mapping the distribution of the intensity of the Raman signal, we identified a characteristic inhomogeneous structure related to the presence of clusters with sizes of 5 µm to 20 µm, indicating inhomogeneous donor distribution caused by flaws introduced during crystal growth. Hence, we propose confocal Raman microscopy as a convenient technique for investigating the homogeneity and quality of doped perovskite surfaces, which are needed for various technological applications. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

Materials research, biomedical research, and semiconductor manufacturing can all benefit from nondestructive, high-resolution methods of analysis. As most materials are heterogeneous, it is important to not only acquire high resolution topographic information, but also to identify the chemical composition of samples. A combination of high resolution microscopy with chemically sensitive spectroscopy combined in one instrument allows the detailed characterization of samples with different analytical techniques. When individual instruments are used, returning to a previously surveyed sample area can be very time consuming if not impossible without surface markers.