Shu Nie, Wei Wu, Shirui Xing, Qingkai Yu, Shin-shem Pei, Kevin F. McCarty
We analyze the layer stacking of bilayer graphene grains grown by chemical
vapor deposition (CVD) on Cu foils. Low-energy electron diffraction and
microscopy establish that the smaller hexagonal layer is located right above
the Cu substrate, not on top of the larger graphene layer. Thus, the lower
layer grows by carbon diffusing to its buried edge. These observations strongly
support a mechanism where the new layer nucleates and grows under the first
layer. We discuss how the underlayer mechanism aids achieving uniform single
layers but presents challenges for growing continuous bilayer films by CVD.
View original:
http://arxiv.org/abs/1202.1031
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