Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Nanoscale. 2013 Jul 21;5(14):6530-7. doi: 10.1039/c3nr01080e. Epub 2013 Jun 12.
Here we present CVD growth of graphene on Ni and investigate the growth mechanism using isotopically labeled (13)C-ethanol as the precursor. Results show that during low-pressure alcohol catalytic CVD (LP-ACCVD), a growth time of less than 30 s yields graphene films with high surface coverage (>80%). Moreover, when isotopically labeled ethanol precursors were sequentially introduced, Raman mapping revealed that both (12)C and (13)C graphene flakes exist. This shows that even at high temperature (∼900 °C) the graphene flakes form independently, suggesting a different growth mechanism for ethanol-derived graphene on Ni from the segregation process for methane-derived graphene. We interpret this growth mechanism using a direct surface-adsorptive growth model in which small carbon fragments catalyzed from ethanol decomposition products first nucleate at metal step edges or grain boundaries to initiate graphene growth, and then expand over the entire metal surface.
我们展示了在 Ni 上的 CVD 石墨烯生长，并使用同位素标记的（13）C-乙醇作为前体来研究生长机制。结果表明，在低压醇催化 CVD（LP-ACCVD）中，生长时间小于 30 秒即可得到具有高表面覆盖率（>80%）的石墨烯薄膜。此外，当引入同位素标记的乙醇前体时，拉曼映射显示（12）C 和（13）C 石墨烯薄片都存在。这表明，即使在高温（约 900°C）下，石墨烯薄片也是独立形成的，这表明在 Ni 上由乙醇衍生的石墨烯的生长机制与由甲烷衍生的石墨烯的分凝过程不同。我们使用直接的表面吸附生长模型来解释这种生长机制，其中乙醇分解产物催化的小碳碎片首先在金属台阶边缘或晶界处成核，以启动石墨烯的生长，然后在整个金属表面上扩展。
