Nanometer structure of carbon fibers studied by different scanning probe microscopy techniques: a comparative investigation

The capability of several different scanning probe microscopy techniques with different sorts of tips for the study of carbon fibers is compared. The objective is to establish the limitations of the available methods to reveal the nanostructure of these materials, although the results will be widely applicable not only to carbon fibers, but to carbon materials in general and many others of a different nature. Scanning tunneling microscopy provided the best results in terms of resolution, followed by tapping mode atomic force microscopy. Contact mode atomic force microscopy yielded a poorer resolution with evident distortions in the observed features. The results are discussed in terms of the finite size and morphology of the probing tips and are additionally supported by numerical simulations of the atomic force microscopy imaging process for the case of a strictly geometrical interaction between tip and surface.