Atomic-scale movement induced in nanoridges by scanning tunneling microscopy on epitaxial graphene grown on 4H-SiC(0001)

Abstract

Nanoscale ridges in epitaxial multilayer graphene grown on the silicon face of 4° off-cut 4H-SiC (0001) were found using scanning tunneling microscopy (STM). These nanoridges are only 0.1 nm high and 25–50 nm wide, making them much smaller than previously reported ridges. Atomic-resolution STM was performed near and on top of the nanoridges using a dual scanning technique in which forward and reverse images are simultaneously recorded. An apparent 100% enlarged graphene lattice constant is observed along the leading edge of the image for both directions. Horizontal movement of the graphene, due to both an electrostatic attraction to the STM tip and weak bonding to the substrate, is thought to contribute to the results.