Effects of Al on epitaxial graphene grown on 6H-SiC(0001)
2014 (English)In: Materials Research Express, ISSN 2053-1591 (print), 2053-1591 (online), Vol. 1, no 1, 1-13 p., 015606Article in journal (Refereed) Published
Aluminum was deposited on epitaxial monolayer-grown graphene on SiC(0001). The effects of annealing up to 1200 Â°C on the surface and interface morphology, chemical composition, and electron band structure were analyzed in situ by synchrotron-based techniques at the MAX Laboratory. After heating at around 400 Â°C, Al islands or droplets are observed on the surface and the collected Si 2p, Al 2p, and C 1s core levels spectra indicate Al intercalation at the graphene SiC interface. Also, the original single Ï -band splits into two, indicating decoupling of the carbon buffer layer and the formation of a quasi-free-standing bilayer-like electronic structure. Further heating at higher temperatures from 700 to 900 Â°C yields additional chemical reactions. Broader core level spectra are then observed and clear changes in the Ï -bands near the Dirac point are detected. More electron doping was detected at this stage since one of the Ï -bands has shifted to about 1.1 eV below the Fermi level. Different ordered phases of (7x7), (4x4), (1x1)Al , and (1x1)G were also observed on the surface in this temperature range. The original single Ï π-band was restored after heating at ~1200°C, although an Al signal was still able to be detected.
Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2014. Vol. 1, no 1, 1-13 p., 015606
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-120851DOI: 10.1088/2053-1591/1/1/015606OAI: oai:DiVA.org:liu-120851DiVA: diva2:849313