Nanosized and crystalline sp 3-bonded carbon materials were prepared over large surface areas up to ~33x51 m 2 from the exposure of few-layer graphene (FLG) to H radicals produced by the hotfilament process at low temperature (below 325 C) and pressure (50 Torr). Hybrid materials were also obtained from the partial conversion of FLG. sp 3-C related peaks from diamond and/or lonsdaleite and/or hybrids of both were detected in UV and visible Raman spectra. C-H bonding was directly detected by Fourier Transform Infrared (FTIR) microscopy over an area of ~150 m 2 and one single component attributed to sp 3-C-H mode was detected in the C-H stretching band showing that carbon is bonded to one single hydrogen and strongly suggesting that the sp 3-C materials obtained are ultrathin films with basal planes hydrogenated. The experimental results are compared to computational predictions and comprehensively discussed. Those materials constitute new synthetic carbon nanoforms after fullerenes, nanodiamonds, carbon nanotubes and graphene. This opens the door to new research in multiple areas for the development of new potential applications and may have wide scientific impact, including for the understanding of extraterrestrial diamond-related structures and polytype formation mechanism(s).

Considering typical spectra of a broad range of carbonaceous materials from gas-shale to nanotubes, various ways by which defects show up in Raman spectra are exampled and discussed. The position, resonance behavior, and linewidth of both the D and G bands are compared, even if in some cases obtaining accurate information on the materials from the fitting parameters is a difficult task. As a matter of fact, even if a full picture is unreachable, defining parameter trends is one acceptable option. Two ways to determine the linewidth, either graphically and or by fitting are proposed in order to be able to compare literature data. The relationship between the crystallite size obtained from the linewidth and from X-ray diffraction, which is complementary to the Tuinstra and Koenig law, is examined. We show that a single approach is not possible unless modeling is performed and therefore that analysis of Raman spectra should be adapted to the specificities of each sample series, i.e., a minimum of knowledge about the materials is always required.

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Graphene-based carbon micro-/nano-cones were prepared by depositing pyrolytic carbon onto individual carbon nanotubes as supports using a specific chemical vapor deposition process. They were investigated by means of high-resolution scanning electron microscopy, low-voltage aberration-corrected transmission electron microscopy, Raman spectroscopy, and molecular dynamics modeling. While the graphenes were confirmed to be perfect, the cone texture was determined to be preferably scroll-like, with the scroll turns being parallel to the cone axis. Correspondingly, many of the concentrically displayed graphenes (actually scroll turns) exhibit the same helicity vector. When radii of curvature are large enough, this could allow for coherent stacking to locally take place in spite of the lattice shift induced by the curvature. A particular care was taken on investigating the cone apexes, in which a specific type of graphene termination was observed, here designated as the "zip" defect. Calculations determined a plausible stable structure that such a defect type may correspond to. This defect was found to generate a very low Raman I D /I D′ band ratio (1.5), for which physical reasons are proposed. Combining our results and that of the literature allowed proposing an identification chart for a variety of defects able to affect the graphene lattice or edges.

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