Self-organized metal-semiconductor epitaxial graphene layer on off-axis 4H-SiC(0001)

Debora Pierucci (1) , Haikel Sediri (1) , Mahdi Hajlaoui (1, 2) , Emilio Velez-Fort (3, 1) , Yannick J. Dappe (4, 5) , Mathieu G. Silly (2) , Rachid Belkhou (2) , Abhay Shukla (3) , Fausto Sirotti (2) , Noelle Gogneau (1) , Abdelkarim Ouerghi (1)

1 LPN - Laboratoire de photonique et de nanostructures
2 SSOLEIL - Synchrotron SOLEIL
3 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
4 GMT - Groupe Modélisation et Théorie
5 SPEC - UMR3680 - Service de physique de l'état condensé

The remarkable properties of graphene have shown promise for new perspectives in future electronics, notably for nanometer scale devices. Here we grow graphene epitaxially on an off-axis 4H-SiC(0001) substrate and demonstrate the formation of periodic arrangement of monolayer graphene on planar (0001) terraces and Bernal bilayer graphene on (112 — 0) nanofacets of SiC. We investigate these lateral superlattices using Raman spectroscopy, atomic force microscopy/ electrostatic force microscopy (AFM/EFM) and X-ray and angle resolved photoemission spectroscopy (XPS/ARPES). The correlation of EFM and ARPES reveals the appearance of permanent electronic band gaps in AB-stacked bilayer graphene on (112 — 0) SiC nanofacets of 150 meV. This feature is confirmed by density functional theory (DFT) calculations. The charge transfer between the substrate and graphene bilayer results in an asymmetric charge distribution between the top and the bottom graphene layers opening an energy gap. This surface organization can be thus defined as self-organized metal–semiconductor graphene.

Keywords: electronic properties; Bernal stacking; off-axis silicon carbide; epitaxial graphene layer; monolayer; bilayer; band gap opening

Domains: Physics [physics]

Debora Pierucci, Haikel Sediri, Mahdi Hajlaoui, Emilio Velez-Fort, Yannick J. Dappe, et al.. Self-organized metal-semiconductor epitaxial graphene layer on off-axis 4H-SiC(0001). Nano Research, 2015, 8 (3), pp.1026-1037. ⟨10.1007/s12274-014-0584-y⟩. ⟨cea-01366518⟩