Evidence for graphene growth by C cluster attachment

Radiation-mode optical microscopy on the growth of graphene

“…The higher E a value than that of the precursor production 41 suggested that the incorporation process is a rate-determining factor. In the literatures by the post-synthesis observation, the activation energy of attachment of the C precursor at the periphery of the graphene grains was evaluated: 2.6 eV for Cu 26 and 2.0 eV for Ru 16 . Therefore, the incorporation of precursors to graphene is considered to be a most likely rate-determining reaction in the present growth conditions.…”

“…If the CVD process is observed in real time, it helps the optimization of parameters and the elucidation of the growth mechanism. To date, the real-time observations of the growth of graphene have been performed in ultra-high vacuum or low-pressure (o20 Pa) conditions on various metal substrates by scanning tunnelling microscopy, scanning transmission electron microscopy, low-energy electron microscopy, in situ Raman spectroscopy, environmental scanning electron microscopy (SEM) and so on [13][14][15][16][17][18][19][20][21][22] . From the viewpoint of scalable production of graphene, however, the combination of CH 4 gas and Cu substrate is considered the most promising, which requires the source gases with relatively high pressure from several Pa to atmospheric pressure [23][24][25][26][27][28][29] .…”

Water adsorption on graphene/Pt(111) at room temperature: A vibrational investigation

“…Moreover, strong effects from the growth method itself are possible. [51][52][53][54][55] Water reactivity strongly depends on both the substrate underneath the graphene sheet as well as the amount and type of defects. We want to point out that our experiments have been performed with a particular type of graphene (quasi-freestanding epitaxial MLG) and under specific conditions.…”

Optimizing long-range order, band gap, and group velocities for graphene on close-packed metal surfaces

“…Concerted experimental [14,17,23,24] and theoretical [54][55][56] effort has been devoted to addressing the graphene growth mechanism on transition metal surfaces. Once the thermal decomposition of the hydrocarbon molecule is complete, which happens at around 450 K ≤ T ≤ 700 K [7,8,47], small carbon clusters reside on the surface.…”

“…Once the thermal decomposition of the hydrocarbon molecule is complete, which happens at around 450 K ≤ T ≤ 700 K [7,8,47], small carbon clusters reside on the surface. Only if the temperature is sufficiently high, T ≥ 700 K [7,47], will these carbon clusters start to form graphene islands [7,47,54,55], given that a critical C adatom concentration is reached [17,23,24,56]. Furthermore, it is now understood that graphene formation proceeds not via monomer attachment but rather through incorporation of a five carbon atom precursor molecule [17,24,56].…”