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Many Raman results appear still contradictory and confusing in consequence of insufficient theoretic fundamentals. Considering huge property differences between carbon species and coatings, their process dependent material structure needs to be sorted out in more detail with better characterizing in order to improve corresponding carbon material and coating results. This can be achieved for many carbon materials in considering that sp2 clusters imbedded in amorphous carbon material correspond to graphenic particles. However, many insufficiently considered aspects need to associate. This is especially concerning recently discussed sp3 atomic rearrangement activation effects, the more detailed incidence of stress and material disorder on Raman peak broadening and peak shifts and some other theoretic aspects concerning the double resonance theory which can be questioned. It appears here that energy and momentum conservation conditions of corresponding Raman scattering model are not always fulfilled and that many predictions based on confinement calculation are not always in agreement with experimental results.
About the author
Stephane Neuville obtained his PhD in plasma physics and advanced thin films (1996) after a longer career in different high tech industries with technical and marketing responsibilities. He is author of several published papers concerning carbon material fundamentals and is acting as an independant consultant in tetrahedral carbon engineering.
