Graphene diamond-like carbon films heterostructure

Abstract

A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ∼25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

Mixed sp2–sp3 Nanocarbon Materials: A Status Quo Review

“…Besides the structural aspects of the GN-diamond transformation, a cross-over between the semiconducting and metallic properties in GN-diamond-like carbon heterostructures were investigated by Zhao and co-workers [75]. The results show that different GN terminations (N, F) strongly affect the electronic properties of the GN nanostructures.…”

First Principle Study of the Attachment of Graphene onto Different Terminated Diamond (111) Surfaces

“…It has a large band gap and possesses excellent properties such as high thermal stability, radiation hardness, chemical resistance, and heat dissipation [7]. There have been some experimental studies on the electronic properties and synthesis of this sp 2 (graphene)-on-sp 3 (diamond) system [6,[8][9][10][11][12]. The graphene-on-diamond system has also been explored in many applications such as high-frequency graphene transistors [13] and spin-polarized conducting wires [14].…”

Graphene-Nanodiamond Heterostructures and their application to High Current Devices

“…However, a limitation to the exploitation of graphene as an electronic material is the near-zero bandgap, which results in a small on-off ratio for transistor devices fabricated from this material 10 11 . Several approaches have been explored to overcome this problem, such as nanoribbon fabrication, graphene hydrogenation and the use of bilayer graphene; these may create a sizable bandgap but also severely degrade the electronic properties of graphene 12 13 14 15 16 . An alternative approach is to modify the supporting substrate material which must inevitably be used when a 2D material is used to fabricated practical devices: The aim being to modify the graphene in terms of band gap creation and doping without severely degrading the carrier transport properties of the graphene layer itself 2 17 .…”