Related Experiment Video
Updated: Jun 7, 2026
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Graphene Islands on Cu foils: the interplay between shape, orientation, and defects
Joseph M Wofford1, Shu Nie, Kevin F McCarty
1Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States.
Nano Letters
|October 29, 2010
Summary
We observed monolayer graphene growth on copper foils. Polycrystalline islands with varied crystallographic alignments form due to nucleation at surface defects, impacting graphene quality.
Area of Science:
- Materials Science
- Surface Science
- Nanotechnology
Background:
- Monolayer graphene synthesis on copper (Cu) foils is crucial for electronic applications.
- Understanding nucleation and growth mechanisms is key to improving graphene quality.
- Previous studies highlight the role of substrate crystallography in graphene growth.
Purpose of the Study:
- To investigate the nucleation and growth dynamics of monolayer graphene on Cu (100) foils.
- To elucidate the crystallographic orientations of graphene islands formed.
- To identify factors influencing graphene quality during growth.
Main Methods:
- Low-energy electron microscopy (LEEM) was employed to observe graphene growth in situ.
- Analysis of island morphology and crystallographic alignment with the Cu substrate.
- In situ observation of surface dynamics at high temperatures (∼790 °C).
Main Results:
- Four-lobed, 4-fold symmetric graphene islands nucleated on the Cu (100) surface.
- Each lobe exhibited a distinct crystallographic orientation relative to the Cu substrate.
- Graphene quality improved above ∼790 °C, but Cu step motion led to surface roughening and mound formation.
- Heterogeneous nucleation at surface imperfections was identified as the origin of polycrystalline islands.
Conclusions:
- The observed polycrystalline nature of graphene islands stems from heterogeneous nucleation at Cu surface defects.
- Angularly dependent growth velocity explains the lobe-shaped evolution of graphene islands.
- Strategies to enhance monolayer graphene quality must mitigate defect generation and surface roughening during high-temperature growth.
Related Concept Videos
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
01:29Imperfections in Crystal Structure: Non-Stoichiometric Defects
Non-stoichiometric defects refer to a type of defect in the crystal structure of a compound where the ratio of its constituent elements deviates from the ideal stoichiometric ratio. There are two main types of non-stoichiometric defects: metal excess defects and metal deficiency defects.Metal excess defects occur when there is a slight surplus of metal ions than what is required by the stoichiometric ratio of the compound. For example, heating a sodium chloride crystal in sodium vapor results...
01:25Imperfections in Crystal Structure: Point, Line and Plane Defects
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...