Reed, B P; Bathen, M E; Ash, J W R; Meara, C J; Zakharov, A A; Goss, J P; Wells, J W; Evans, D A; Cooil, S P (2022) Diamond (111) surface reconstruction and epitaxial graphene interface. Physical Review B, 105 (20). 205304

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Abstract

The evolution of the diamond (111) surface as it undergoes reconstruction and subsequent graphene formation is investigated with angle-resolved photoemission spectroscopy, low energy electron diffraction, and complementary density functional theory calculations. The process is examined starting at the C(111)-(2×1) surface reconstruction that occurs following detachment of the surface adatoms at 920 °C, and continues through to the liberation of the reconstructed surface atoms into a free-standing monolayer of epitaxial graphene at temperatures above 1000 °C. Our results show that the C(111)-(2×1) surface is metallic as it has electronic states that intersect the Fermi-level. This is in strong agreement with a symmetrically π-bonded chain model and should contribute to resolving the controversies that exist in the literature surrounding the electronic nature of this surface. The
graphene formed at higher temperatures exists above a newly formed C(111)-(2 × 1) surface and appears to have little substrate interaction as the Dirac-point is observed at the Fermi-level. Finally, we demonstrate that it is possible to hydrogen terminate the underlying diamond surface by means of plasma processing without removing the graphene layer, forming a graphene-semiconductor interface. This could have particular relevance for doping the graphene formed on the diamond (111) surface via tuneable substrate interactions as a result of changing the terminating species at the diamond-graphene interface by plasma processing.

Item Type:	Article
Keywords:	diamond; graphene; DFT; ARPES; electronic structure; surface conductivitity; quantum
Subjects:	Nanoscience > Nano-Materials
Divisions:	Chemical & Biological Sciences
Identification number/DOI:	10.1103/PhysRevB.105.205304
Last Modified:	03 May 2023 13:40
URI:	https://eprintspublications.npl.co.uk/id/eprint/9700