Origin of layer decoupling in ordered multilayer graphene grown by high-temperature sublimation on C-face 4H-SiC

Ingemar Persson,Philipp Kühne,Mathias Schubert,Johanna Rosen,Rositsa Yakimova,Nerijus Armakavicius,Per O Å Persson,Chamseddine Bouhafs,Vallery Stanishev,Tino Hofmann,Vanya Darakchieva

doi:10.1063/1.5134862

Abstract

We study the origin of layer decoupling in ordered multilayer graphene grown by high temperature sublimation on C-face 4H-SiC. The mid-infrared optical Hall effect technique is used to determine the magnetic field dependence of the inter-Landau level transition energies and their optical polarization selection rules, which unambiguously show that the multilayer graphene consists of electronically decoupled layers. Transmission electron microscopy reveals no out-of-plane rotational disorder between layers in the stack, which is in contrast to what is typically observed for C-face graphene grown by low temperature sublimation. It is found that the multilayer graphene maintains AB-stacking order with increased interlayer spacing by 2.4%–8.4% as compared to highly oriented pyrolytic graphite. Electron energy loss spectroscopy mapping reveals Si atoms trapped in between layers, which are proposed to be the cause for the observed increased interlayer spacing leading to layer decoupling. Based on our results, we propose a defect-driven growth evolution mechanism for multilayer graphene on C-face SiC via high temperature sublimation.

Highlights

Layer decoupling has previously been attributed to an outof-plane rotational disorder between graphene sheets in the stack for multilayer graphene (MLG) grown at temperatures below 1700 ○C.8,14 More recently, we have shown that MLG grown by high temperature sublimation (1850 ○C–2000 ○C) on the C-face of both 4H-silicon carbide (SiC) and
We study the origin of layer decoupling in ordered multilayer graphene grown by high temperature sublimation on C-face 4H-SiC
Transmission electron microscopy reveals no out-of-plane rotational disorder between layers in the stack, which is in contrast to what is typically observed for C-face graphene grown by low temperature sublimation

Summary

APL Materials

Ingemar Persson,1,a) Nerijus Armakavicius,2,a) Chamseddine Bouhafs, Vallery Stanishev, Philipp Kühne, Tino Hofmann, Mathias Schubert, Johanna Rosen, Rositsa Yakimova, Per O.

Landau level energy En for single layer graphene is given by

Findings

The MLG regions with intermediate thickness also demonstrate