How Low Nucleation Density of Graphene on CuNi Alloy is Achieved
Date
2018-03
Authors
Liu, Yifan
Wu, Tianru
Yin, Yuling
Zhang, Xuefu
Yu, Qingkai
Searles, Debra J.
Ding, Feng
Yuan, Qinghong
Xie, Xiaoming
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
CuNi alloy foils are demonstrated to be one of the best substrates for synthesizing large area single-crystalline graphene because a very fast growth rate and low nucleation density can be simultaneously achieved. The fast growth rate is understood to be due the abundance of carbon precursor supply, as a result of the high catalytic activity of Ni atoms. However, a theoretical understanding of the low nucleation density remains controversial because it is known that a high carbon precursor concentration on the surface normally leads to a high nucleation density. Here, the graphene nucleation on the CuNi alloy surfaces is systematically explored and it is revealed that: i) carbon atom dissolution into the CuNi alloy passivates the alloy surface, thereby drastically increasing the graphene nucleation barrier; ii) carbon atom diffusion on the CuNi alloy surface is greatly suppressed by the inhomogeneous atomic structure of the surface; and iii) a prominent increase in the rate of carbon diffusion into the bulk occurs when the Ni composition is higher than the percolation threshold. This study reveals the key mechanism for graphene nucleation on CuNi alloy surfaces and provides a guideline for the catalyst design for the synthesis of graphene and other 2D materials.
Description
Keywords
carbon diffusion, graphene nucleation, percolation, CuNi alloys, Ingram School of Engineering
Citation
Liu, Y., Wu, T., Yin, Y., Zhang, X., Yu, Q., Searles, D. J., Ding, F., Yuan, Q., & Xie, X. (2018). How low nucleation density of graphene on CuNi alloy is achieved. Advanced Science, 5(6).
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Rights Holder
© 2018 The Authors.
Rights License
This work is licensed under a Creative Commons Attribution 3.0 United States License.