Properties of epitaxial graphene grown on C-face SiC compared to Si-face

Abstract

Epitaxial graphene of uniform thickness prepared on SiC is of great interest for various applications. On the Si-face, large area uniformity has been achieved, and there is a general consensus about the graphene properties. A similar uniformity has yet not been demonstrated on the C-face where the graphene has been claimed to be fundamentally different. A rotational disorder between adjacent graphene layers has been reported and suggested to explain why multilayer C-face graphene show the p-band characteristic of monolayer graphene. Utilizing low energy electron microscopy, x-ray photoelectron electron microscopy, low energy electron diffraction, and photoelectron spectroscopy, we investigated the properties of C-face graphene prepared by sublimation growth. We observe the formation of micrometer-sized crystallographic grains of multilayer graphene and no rotational disorder between adjacent layers within a grain. Adjacent grains are in general found to have different azimuthal orientations. Effects on C-face graphene by hydrogen treatment and Na exposure were also investigated and are reported. Why multilayer C-face graphene exhibits single layer electronic properties is still a puzzle, however.

Probing the electronic properties of graphene on C-face SiC down to single domains by nanoresolved photoelectron spectroscopies

“…At present, there exist several interpretations about the rotational disorder on this system. Several groups reported that the disorder is due to the rotation between graphene layers inside one single domain [14,15], the Bernal stacked azimuthally disordered graphene domains [12,[22][23][24], or a combination of AB stacked and twisted multilayers [26]. We now present our results obtained from graphene with different thicknesses measured by classical and nano photoelectron spectroscopies.…”

“…Based on theoretical calculations, renormalization of the Fermi velocity near the Dirac point is expected for very small twist angles [20,21]. On the other hand, Johansson and co-workers [12,22,23] have conducted μ-LEED and x-ray photoemission electron microscopy (XPEEM) studies that enabled them to measure single graphene domains on the C-face. The results showed the coexistence of micrometersized domains of single and multilayer graphene with different azimuthal orientations and no twisted layers within the grains.…”

Epitaxial Graphene on SiC: A Review of Growth and Characterization

“…The remaining C forms a graphene film on the surface. However, the surface reconstructions and growth kinetics for each polar surface are different, resulting in different graphene growth rates, growth morphologies and electronic properties [30,[73][74][75]. Yakimova et al have analyzed the conditions for large-area graphene formation on SiC substrate [21].…”

Study of novel electronic materials by mid-infrared and terahertz optical Hall effect

“…Graphene is atomic layer of sp 2 -hybridized carbon atoms covalently bonded in a honeycomb lattice via three in-plane σ-bonds and a remaining dangling π-bond EG grown on semi-insulating silicon carbide (SiC) substrates has a high potential for integration in the existing planar electronic devices technologies. While growth of graphene on the C-face (0001) of SiC substrates is difficult to control, the Si-face (0001) provides high quality, homogenous monolayer (ML) and bilayer (BL) graphene at a wafer scale, due to a self-consistent nature of the growth process [3][4][5]. Prototype devices based on EG have been demonstrated [6][7][8][9].…”