Large-scale transfer and characterization of macroscopic periodically nano-rippled graphene

Nano-rippled graphene, a structurally modified graphene, presents a novel material with a large range of possible applications including sensors, electrodes, coatings, optoelectronics, spintronics and straintronics. In this work we have synthesized macroscopic single layer graphene with well-defined uniaxial periodic modulation on a stepped Ir(332) substrate and transferred it to a dielectric support. The applied fast transfer process does not damage the Ir crystal which can be repeatedly used for graphene synthesis. Upon transfer, a millimeter sized graphene flake with a uniform periodic nano-ripple structure is obtained, which exhibits a macroscopically measurable uniaxial strain. The periodic one dimensional arrangement of graphene ripples was confirmed by atomic force microscopy and polarized Raman measurements. An important feature of this system is that the graphene lattice is rotated in several different, well-defined orientations with respect to the direction of the ripple induced uniaxial strain. Moreover, geometry of the ripples can be modified by changing the graphene synthesis parameters.