Raman scattering studies of graphene under high pressure

Abstract

The effect of pressure -by definition a 3-dimensional concept -on 2-dimensional systems brings a number of fundamental questions, which have been partly answered through newly engineered samples and experimental setups. In this review of the high-pressure Raman studies of graphene, we will in particular underline the importance of the presence of a supporting substrate and its role for the production of biaxial strain conditions in high pressure experiments. Raman shifts observed during these experiments may be related to the strain induced by the substrate rather than by the applied pressure, graphene stress, and hydrostatic pressure not being straightforwardly equivalent in this case of a composite 2D-on-3D material. We will also consider the effects of the nature of the substrate surface, the nature of the pressure transmitting media, as well as the effect of the number of layers on the high-pressure response of the 2D-system, by using the phonon behavior as strain probe as pressure is applied. The effects of adhesion and of strain transfer from the substrate to the 2D-system will be at the heart of our discussion.

Size‐controlled graphene‐based materials prepared by annealing of pitch‐based cokes: G band phonon line broadening effects due to high pressure, crystallite size, and merging with D′ band

“…[21] No significant medium effect is expected, as the samples are composed of grains of several micrometers. If we compare this value with recent findings [14,15] in graphene, taking care to consider medium and substrate effects, a similar value is found. The linewidth increases significantly with increasing pressure for pressure higher than 8 GPa.…”

“…This threshold at 1% of strain has been previously attributed to the formation of Z carbon with experiment conducted on graphite. [15] With higher pressure, bonding changes lead to superhard graphite. [23] The appearance of T band reported in Amsler et al [16] that is related to sp 3 bonded to graphene layer [24] is definitively an indicator that this carbon hybridization change is partial, explaining why G band is still present without a jump.…”

“…Initially, it remains constant up to 9 GPa and then increases abruptly at higher pressure. This takes place irrespective of the type pressure transmitting medium (or even no medium) . So far, no high‐pressure Raman measurements have been reported in literature for a series of samples with controlled degrees of graphitization and the controlled particle size.…”

“…This takes place irrespective of the type pressure transmitting medium (or even no medium). [14][15][16][17] So far, no high-pressure Raman measurements have been reported in literature for a series of samples with controlled degrees of graphitization and the controlled particle size. Different degrees of graphitization [18] are obtained by annealing a carbon at different temperatures under inert gas.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Jorio presented a dedication to the life‐long contributions of Mildred S. Dresselhaus (1930–2017) in the same special issue of JRS highlighting her contributions to our understanding of graphite, graphite intercalated compounds, graphite ion‐implantation, graphite fibers, fullerenes, carbon nanotubes, and two‐dimensional systems, starting from graphene . Other reviews in the special issue on graphene and related 2D materials, previously described above, were the following: Beams on Tip‐enhanced Raman scattering of graphene ; Faugeras and co‐workers on Raman scattering of graphene‐based systems in high magnetic fields ; Bendiab et al on Unravelling external perturbation effects on the optical phonon response of graphene ; Lee and Cheong on Resonance Raman effects in transition metal dichalcogenides ; Machon et al on Raman scattering studies of graphene under high pressure ; and Ribeiro and co‐workers on the Raman spectroscopy in black phosphorus . Huang and colleauges provided a conference report from the 5th International Taiwan Symposium on Raman Spectroscopy (2017) and Taiwan Association of Raman Spectroscopy Summer Camp .…”