Raman measurements were acquired on a WITec Alpha 300 R confocal Raman microscope in backscattering geometry. Multiwavelength excitation Raman measurements using 488, 532 and 785 nm lasers were performed on all samples. The beam was focused on the sample with a microscope objective, resulting in a diameter spot of 800 nm for 488 nm laser, 1 μm for 532 nm laser, and 1.2 μm for 785 nm laser, and reaching a radiant power of the order of 300 μW. Laser power conditions were selected based on a power study, which involved measuring Raman spectrum at the same point on the material with increasing laser power densities, starting from the lowest power available. For each laser power, the spectrum was monitored for changes in peak positions, peak widths, or the appearance of new peaks. The highest power for which no changes in these parameters were observed was taken as the optimal laser power for measurements. The backscattered light was analyzed with two spectrometers: a 300 mm lens-based spectrometer with a grating of 1800 g/mm equipped with a thermoelectrically cooled CCD for 488 and 532 nm excitation and a 400 mm lens-based spectrometer with a grating of 1200 g/mm equipped with a cooled deep-depletion CCD for 785 nm excitation. All spectra were calibrated based on the reference Si Raman spectrum.