Multilayer graphene, Moir\'e patterns, grain boundaries and defects identified by scanning tunneling microscopy on the m-plane, non-polar surface of SiC

摘要

Epitaxial graphene is grown on a non-polar n+ 6H-SiC m-plane substrate andstudied using atomic scale scanning tunneling microscopy. Multilayer grapheneis found throughout the surface and exhibits rotational disorder. Moir\'epatterns of different spatial periodicities are found, and we found that as thewavelength increases, so does the amplitude of the modulations. Thisrelationship reveals information about the interplay between the energyrequired to bend graphene and the interaction energy, i.e. van der Waalsenergy, with the graphene layer below. Our experiments are supported bytheoretical calculations which predict that the membrane topographicalamplitude scales with the Moir\'e pattern wavelength, L as L^-1 + \alpha L^-2.