Direct graphene growth on metal oxides by molecular epitaxy

Patent metadata

Field	Value
Publication number	US-9624600-B2
Application number	US-201214362619-A
Country	US
Kind code	B2
Filing date	Dec 6, 2012
Priority date	Dec 6, 2011
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Direct growth of graphene on Co 3 O 4 (111) at 1000 K was achieved by molecular beam epitaxy from a graphite source. Auger spectroscopy shows a characteristic sp 2 carbon lineshape, at average carbon coverages from 0.4-3 monolayers. Low energy electron diffraction (LEED) indicates (111) ordering of the sp 2 carbon film with a lattice constant of 2.5 (±0.1) Å characteristic of graphene. Six-fold symmetry of the graphene diffraction spots is observed at 0.4, 1 and 3 monolayers. The LEED data also indicate an average domain size of ˜1800 Å, and show an incommensurate interface with the Co 3 O 4 (111) substrate, where the latter exhibits a lattice constant of 2.8 (±0.1) Å. Core level photoemission shows a characteristically asymmetric C(1s) feature, with the expected lr to lr* satellite feature, but with a binding energy for the three monolayer film of 284.9 (±0.1) eV, indicative of substantial graphene-to-oxide charge transfer.

First claim

What is claimed is:

1. A method of forming a composition of matter comprising macroscopically continuous layers of graphene on a metal oxide surface, wherein said method comprises steps of:
forming a layer of a metal consisting of cobalt and having a first major surface;
annealing said first major surface in oxygen to form an oxide of said metal on said first major surface; and
forming more than one layer of macroscopically continuous graphene on said metal oxide layer by carbon molecular beam epitaxy (MBE) thereby creating an oxide/graphene interface between said metal oxide layer and a first layer of graphene, wherein said oxide/graphene interface is incommensurate, without reconstruction of the metal oxide surface, thus yielding C 6V symmetry in said first layer of graphene,
wherein said step of annealing and said step of forming more than one layer of macroscopically continuous graphene are both conducted at temperatures of not more than one thousand degrees Kelvin.

2. A composition of matter comprising a macroscopically continuous multilayer film of graphene on a magnetically polarizable metal oxide creating a graphene/oxide interface between a surface of said metal oxide and a first layer of graphene,
wherein said metal oxide consists of cobalt oxide and is in turn on a room temperature ferromagnet, wherein the graphene/oxide interface is incommensurate, without reconstruction of said metal oxide surface, thus yielding C 6V symmetry in said first layer of graphene.

3. The composition of matter of claim 2 , wherein said composition of matter comprises a graphene field effect transistor, a coherent spin field effect transistor, a magnetic tunnel junction or switch.

Assignees

• Univ North Texas

Inventors

• Kelber Jeffry A

Classifications

• H10P14/3406

  Carbon, e.g. diamond-like carbon · CPC title

• H10P14/3238

  being insulating materials · CPC title

• H10P14/2911

  Arsenides · CPC title

• H10P14/2905

  Silicon, silicon germanium or germanium · CPC title

• H10P14/36

  characterised by treatments done before the formation of the materials · CPC title