Universal Segregation Growth Approach to Wafer-Size Graphene from Non-Noble Metals

Abstract

Graphene has been attracting wide interests owing to its excellent electronic, thermal, and mechanical performances. Despite the availability of several production techniques, it is still a great challenge to achieve wafer-size graphene with acceptable uniformity and low cost, which would determine the future of graphene electronics. Here we report a universal segregation growth technique for batch production of high-quality wafer-scale graphene from non-noble metal films. Without any extraneous carbon sources, 4 in. graphene wafers have been obtained from Ni, Co, Cu-Ni alloy, and so forth via thermal annealing with over 82% being 1-3 layers and excellent reproducibility. We demonstrate the first example of monolayer and bilayer graphene wafers using Cu-Ni alloy by combining the distinct segregation behaviors of Cu and Ni. Together with the easy detachment from growth substrates, we believe this facile segregation technique will offer a great driving force for graphene research.

Rational design of a binary metal alloy for chemical vapour deposition growth of uniform single-layer graphene

“…All of these factors contribute to the uniformity and layer distribution of the obtained graphene films. For catalytic metals with high carbon solubility and a sharp temperature dependency, such as Ni and cobalt (Co) (~1.2 and 1.0 at.% at 1,000 o C respectively), a massive carbon species would segregate from bulk metals and precipitate on the surface during cooling 17 . This type of non-equilibrium precipitation process is believed to be the origin of inhomogeneous graphene growth, especially at the grain boundaries of polycrystalline metal films, which serve as nucleation centres for multilayer graphene growth 18 .…”

Segregation Phenomenon and Its Control in the Catalytic Growth of Graphene

“…Reprinted with permission [57] [66,67,29] . 基于这一考量, 我们 [29] 开展了低真空条件下 的多晶金属表面的碳偏析研究, 成功地建立了普适性的 廉价生长大面积高质量石墨烯的偏析方法.…”

“…[29] [73] ; 与 单层石墨烯不同, 具有 AB 堆垛的双层石墨烯在施加电 场的情况下可以打开高达 250 meV 的带隙 [74] , 使其应用 于逻辑器件成为可能; 三层石墨烯又会表现出新的量子 霍尔现象 [75] . 另外, 将石墨烯应用到透明导电薄膜领域 时, 单层石墨烯是不够的, 往往需要少层的石墨烯来获 得较低的面电阻 [13] .…”

“…基于这一指导思想, 我们围绕石墨烯表面生长中的偏析问题, 开展了一系列 研究探索, 建立了普适性的廉价、均匀生长大面积高质 量石墨烯的偏析生长方法 [29] . 通过二元合金的设计, 在 Cu-Ni 合金基底上实现了单层和双层石墨烯的控制生 长 [46] , 并利用共偏析法制备出掺杂石墨烯 [47] .…”

Wafer-scale graphene on 2 inch SiC with uniform structural and electrical characteristics

“…So far, the two typical, viable methods of fabricating largearea graphene are thermal decomposition of SiC and chemical vapor deposition (CVD) on metal substrates. Large-area graphene grown by CVD has potential applications in transparent electrodes and flexible displays [7][8][9][10], while wafer-scale epitaxial graphene (EG) grown on SiC has potential in high frequency devices [11] and integrated circuits (ICs) [12,13] because of its compatibility with current IC procedures. Currently, graphene grown by CVD has achieved a size of more than 30 inches [4].…”