Graphene Induced Surface Reconstruction of Cu

TL;DR

This study uses STM to observe how graphene induces a surface reconstruction on copper, revealing periodic stripe patterns caused by strain and partial dislocations, and shows that graphene can decouple from the copper substrate.

Contribution

It provides atomic-scale evidence of graphene-induced surface reconstruction on copper and characterizes the resulting stripe patterns and decoupling effects.

Findings

Periodic stripe patterns formed on Cu surface after graphene coverage

Surface reconstruction caused by strain from graphene overlayer

Graphene grains are more decoupled from Cu compared to previous studies

Abstract

An atomic-scale study utilizing scanning tunneling microscopy (STM) in ultrahigh vacuum (UHV) is performed on large single crystalline graphene grains synthesized on Cu foil by a chemical vapor deposition (CVD) method. After thermal annealing, we observe the presence of periodic surface depressions (stripe patterns) that exhibit long-range order formed in the area of Cu covered by graphene. We suggest that the observed stripe pattern is a Cu surface reconstruction formed by partial dislocations (which appeared to be stair-rod-like) resulting from the strain induced by the graphene overlayer. In addition, these graphene grains are shown to be more decoupled from the Cu substrate compared to previously studied grains that exhibited Moir\'e patterns.