The Role and Control of Residual Bulk Oxygen in the Catalytic Growth of 2D Materials
The Role and Control of Residual Bulk Oxygen in the Catalytic Growth of 2D Materials
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DOI：
10.1021/acs.jpcc.9b03808
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发表时间：
2019-07-04
影响因子：
3.7
通讯作者：
Hofmann, Stephan
中科院分区：
文献类型：
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作者：
Burton, Oliver J.;Babenko, Vitaliy;Hofmann, Stephan
我们系统地研究了铜箔催化剂中的残余氧对石墨烯化学气相沉积(CVD)的影响。虽然氧化被广泛用于去除金属催化剂中的杂质和控制石墨烯的成核密度，但我们发现微量的剩余体氧浓度会显著恶化生长的石墨烯的质量，突出表现为拉曼D/G比的增加，生长后刻蚀的倾向增加，以及多层石墨烯成核的比例增加。从商业铜箔出发，我们证明了在初始氧化后的简单氢气退火步骤允许我们降低飞行时间二次离子质谱仪测量的剩余氧水平，以生产质量显著更高的石墨烯。这可以有效地与10分钟的短碳氢化合物暴露时间相结合，实现几乎完全的单层石墨烯覆盖，适合新兴的工业应用。我们证明了剩余氧对Fe催化的h-BN CVD有同样重要的影响，并与冶金、催化和真空科学中的众所周知的过程相似地讨论了潜在的机制。
We systematically study the effects of residual oxygen in the bulk of Cu foil catalysts on the chemical vapor deposition (CVD) of graphene. While oxidation is widely used to remove impurities in metal catalysts and to control the nucleation density of graphene, we show that minute concentrations of residual bulk oxygen can significantly deteriorate the quality of as-grown graphene highlighted by an increased Raman D/G ratio, increased propensity to postgrowth etching, and increased fraction of multilayer graphene nucleation. Starting from commercial Cu foils, we show that a simple hydrogen annealing step after the initial oxidation allows us to lower the residual oxygen level as measured by time-of-flight secondary ion mass spectrometry to produce graphene of significantly higher quality. This can be effectively combined with a short hydrocarbon exposure time of 10 min to achieve near full monolayer graphene coverage, suitable for emerging industrial applications. We show that residual oxygen can have an equally significant impact on Fe-catalyzed h-BN CVD and discuss the underlying mechanisms with parallels to well-known processes in metallurgy, catalysis, and vacuum science.