Formation of Graphene Nanofin Networks on Graphene/SiC(0001) by Molecular Beam Epitaxy

A graphene nanofin consists of few-layer graphene and sticks out from the surface like a fin. To understand what graphene nanofin is and gain insight into its formation mechanism, we grew graphene at various substrate temperatures by gas-source molecular beam epitaxy (MBE) on previously prepared epitaxial graphene formed on a SiC(0001). Then, the surfaces were observed using atomic force microscopy, transmission electron microscopy, and low-energy electron microscopy (LEEM). We found the graphene nanofin formation at the growth temperature from 600 to 915 degrees C. The LEEM and low-energy electron diffraction observations reveal that the crystal axes of the graphene layer are completely random, although their (0001) axes are aligned. This experimentally supports a formation mechanism where the nanofins are formed by the collision between incommensurate domains of graphene at their boundaries. (C) 2012 The Japan Society of Applied Physics