Nanoscience Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FF, United Kingdom.
Nanotechnology. 2018 Nov 1;29(45):455705. doi: 10.1088/1361-6528/aadd6d. Epub 2018 Aug 29.
We have used ultrahigh vacuum scanning tunneling microscopy (STM) to investigate the effect of thermal annealing of graphene grown by chemical vapor deposition on a Cu(110) foil. We show that the annealing appears to induce a reconstruction of the Cu surface along the [210] direction, with a period of 1.43 nm. Such reconstructions have been ascribed to the tensile strain induced in the Cu surface by its differential thermal expansion relative to the graphene over-layer, but we show that it is in fact a moiré pattern due to interference between the graphene and the underlying atomic lattice as evidenced by the appearance of an odd-even transition only observed due to misorientation of the top layer of a layered crystal. This highlights that the analysis of STM measurements of graphene on metal surfaces should take such interference effects into account and that the graphene-Cu interface is more complex than previously thought.
我们使用超高真空扫描隧道显微镜（STM）研究了化学气相沉积生长在 Cu(110)箔上的石墨烯的热退火对其的影响。我们表明，退火似乎会诱导 Cu 表面沿着[210]方向发生重构，其周期为 1.43nm。这种重构归因于 Cu 表面因相对于石墨烯覆盖层的热膨胀系数不同而产生的拉伸应变，但我们表明，它实际上是由于石墨烯与下面的原子晶格之间的干涉而产生的莫尔图案，这可以通过仅由于层状晶体顶层的取向失配而观察到的奇偶过渡来证明。这突出表明，对金属表面上石墨烯的 STM 测量的分析应该考虑到这种干涉效应，并且石墨烯-Cu 界面比以前认为的要复杂。
