Arjmandi-Tash Hadi, Schneider Grégory F
Faculty of Science, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands.
ACS Mater Au. 2022 Mar 9;2(2):79-84. doi: 10.1021/acsmaterialsau.1c00047. Epub 2021 Dec 17.
In chemical vapor deposition of graphene, crossing over the melting temperature of the bulk catalyst is an effective approach to heal the defects and thus improve the crystallinity of the lattice. Here, electromagnetic absorption (the capability of metals to absorb radiated thermal energy) yields a thin skin of liquid metal catalyst at submelting temperatures, allowing the growth of high quality graphene. In fact, a chromium film initially deposited on one side of a copper foil absorbs the thermal energy radiated from a heating stage several times more effectively than a plain copper foil. The resulting migration of the chromium grains to the other side of the foil locally melts the copper, improving the crystalline quality of the growing graphene, confirmed by Raman spectroscopy. The process duration is therefore dramatically minimized, and the crystallinity of the graphene is maximized. Remarkably, the usual annealing step is no more necessary prior to the growth which together with unlocking the direct healing of defects in the growing graphene, will unify growth strategies between a range of catalysts.
在石墨烯的化学气相沉积过程中，使块状催化剂超过熔点温度是修复缺陷从而提高晶格结晶度的有效方法。在此，电磁吸收（金属吸收辐射热能的能力）在亚熔点温度下产生一层液态金属催化剂薄膜，从而实现高质量石墨烯的生长。实际上，最初沉积在铜箔一侧的铬膜比普通铜箔更有效地吸收来自加热台辐射的热能。铬颗粒由此迁移到箔片的另一侧，局部熔化铜，改善了生长中石墨烯的晶体质量，这一点通过拉曼光谱得到证实。因此，该过程的持续时间大幅缩短，石墨烯的结晶度达到最大化。值得注意的是，在生长之前不再需要通常的退火步骤，这与直接修复生长中石墨烯的缺陷相结合，将统一一系列催化剂之间的生长策略。
