Abstract
Zigzag-edge graphene sidewall ribbons grown on 6H-SiC {112n} facet walls are ballistic conductors. It is assumed that graphene sidewall ribbons grown on 4H-SiC {112n} facets would also be ballistic. In this work, we show that SiC polytype indeed matters: ballistic sidewall graphene ribbons only grow on 6H-SiC facets. 4H and 4H-passivated sidewall graphene ribbons are diffusive conductors. Detailed photoemission and microscopy studies show that 6H-SiC sidewall zigzag ribbons are metallic with a pair of n-doped edge states associated with asymmetric edge terminations. In contrast, 4H-SiC zigzag ribbons are strongly bonded to the SiC, severely distorting the ribbon's π bands. H2 passivation of the 4H ribbons returns them to a metallic state but they show no evidence of edge states in their photoemission-derived band structure.
| Original language | English |
|---|---|
| Article number | 045425 |
| Journal | Physical Review B |
| Volume | 100 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jul 30 2019 |
Bibliographical note
Publisher Copyright:© 2019 American Physical Society.
Funding
This research was supported by the National Science Foundation under Grant No. DMR-1401193 (E.H.C.). A.L.M. acknowledges a travel grant from the School of Physics at Georgia Tech. A.T. acknowledges support from the Agence Nationale de la Recherche (France) under contract CoRiGraph. A portion of the work (multiprobe STM) was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility.
| Funders | Funder number |
|---|---|
| National Science Foundation | |
| Directorate for Mathematical and Physical Sciences | 1401193 |
| Agence Nationale de la Recherche |