Influence of lattice orientation on growth and structure of graphene on Cu(001)

TL;DR

This study investigates how the lattice orientation of graphene affects its growth and structure on Cu(001), revealing anisotropic growth patterns, domain shapes, and moire patterns influenced by lattice alignment.

Contribution

It provides new insights into the anisotropic growth behavior and lattice orientation effects of graphene on Cu(001), supported by experimental observations and geometric modeling.

Findings

Graphene domains grow anisotropically into lens shapes aligned with Cu<100> directions.

Kink-mediated adatom attachment influences growth orientation and domain shape.

Moire pattern evolution correlates with graphene lattice orientation.

Abstract

We have used low-energy electron microscopy and diffraction to examine the significance of lattice orientation in graphene growth on Cu(001). Individual graphene domains undergo anisotropic growth on the Cu surface, and develop into lens shapes with their long axes roughly aligned with the Cu<100> in-plane directions. The long axis of a lens-shaped domain is only rarely oriented along a C<11> direction, suggesting that carbon attachment at "zigzag" graphene island edges is unfavorable. A kink-mediated adatom attachment process is consistent with the behavior observed here and reported in the literature. The details of the ridged moire pattern formed by the superposition of the graphene lattice on the (001) Cu surface also evolve with the graphene lattice orientation, and are predicted well by a simple geometric model. Managing the kink-mediated growth mode of graphene on Cu(001) will be necessary for the continued improvement of this graphene synthesis technique.