This report introduces a method for fabricating graphene at low temperatures via chemical vapor deposition enabled by ultrathin (∼1 nm) nickel-gold (Ni-Au) catalysts. The unique combination of high carbon (C) solubility Ni, low C solubility Au, and an ultrathin layer of a catalyst demonstrates the effectiveness to produce graphene at 450 °C with the layer number independent of growth duration. In contrast to grain-boundary defined catalyst morphology found in thicker (>20 nm) metal catalysts, the ultrathin catalyst morphology leads to the formation of nanoscale metal “islands” during the growth process, which results in curved graphene covering the catalyst. To test the effect of preactivation of the ultrathin catalyst for the formation of graphene, a preanneal process of the catalyst followed by the introduction of a carbon precursor was also investigated. The preanneal process resulted in the formation of carbon nanotubes (CNTs) in lieu of graphene, displaying the impact of the catalytic surface treatment in relation to the produced materials. The results and discussion presented here detail a low-temperature nanoscale manufacturing process that allows for the production of either graphene or CNTs on an ultrathin catalyst.

中文翻译：

---

超薄合金催化剂实现石墨烯薄膜的低温化学气相沉积生长

本报告介绍了一种通过超薄（~1 nm）镍金（Ni-Au）催化剂实现的化学气相沉积在低温下制造石墨烯的方法。高碳 (C) 溶解度 Ni、低 C 溶解度 Au 和超薄催化剂层的独特组合证明了在 450°C 下生产石墨烯的有效性，层数与生长持续时间无关。与在较厚（> 20 nm）金属催化剂中发现的晶界定义的催化剂形态相反，超薄催化剂形态导致在生长过程中形成纳米级金属“岛”，从而导致弯曲的石墨烯覆盖催化剂。为了测试超薄催化剂的预活化对石墨烯形成的影响，还研究了催化剂的预退火过程，然后引入碳前体。预退火过程导致形成碳纳米管 (CNT) 代替石墨烯，显示出催化表面处理对生产材料的影响。此处介绍的结果和讨论详细介绍了一种低温纳米制造工艺，该工艺允许在超薄催化剂上生产石墨烯或碳纳米管。