Campus Units

Chemistry, Materials Science and Engineering, Physics and Astronomy, Ames Laboratory

Document Type


Publication Version

Submitted Manuscript

Publication Date


Journal or Book Title

The Journal of Physical Chemistry Letters




Paradoxically a very broad diffraction background, named the Bell-Shaped-Component (BSC), has been established as a feature of graphene growth. Although the BSC has been present in the earlier literature it has been ignored. Recent diffraction studies as a function of electron energy have shown that the BSC is not related to scattering interference. The BSC is a very strong effect, but its origin is still unclear. Here, additional experiments are carried out as a function of temperature while monitoring changes in the intensity of different spots over the range that single-layer-graphene (SLG) grows. Quantitative fitting of the profiles shows that the BSC follows the increase of the G(10) spot, proving directly that BSC is an indicator of high quality graphene. Additional metal deposition experiments provide more information about the BSC. The BSC is insensitive to metal deposition and it increases with metal intercalation, because a more uniform interface forms between graphene and SiC. These experiments support the conclusion that the BSC originates from electron spatial confinement within SLG and surprisingly it is an excellent measure of graphene uniformity, instead of film disorder.


This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acs.jpclett.0c02113. Posted with permission.

Copyright Owner

American Chemical Society



File Format


Published Version