Hydrogen intercalation of graphene grown on 6H-SiC(0001)
2011 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 605, no 17-18, 1662-1668 p.Article in journal (Refereed) Published
Atomic hydrogen exposures on a monolayer graphene grown on the SiC(0001) surface are shown to result in hydrogen intercalation. The hydrogen intercalation induces a transformation of the monolayer graphene and the carbon buffer layer to bi-layer graphene without a buffer layer. The STM, LEED, and core-level photoelectron spectroscopy measurements reveal that hydrogen atoms can go underneath the graphene and the carbon buffer layer and bond to Si atoms at the substrate interface. This transforms the buffer layer into a second graphene layer. Hydrogen exposure results initially in the formation of bi-layer graphene islands on the surface. With larger atomic hydrogen exposures, the islands grow in size and merge until the surface is fully covered with bi-layer graphene. A (root 3 x root 3)R30 degrees periodicity is observed on the bi-layer areas. ARPES and energy filtered XPEEM investigations of the electron band structure confirm that after hydrogenation the single pi-band characteristic of monolayer graphene is replaced by two pi-bands that represent bi-layer graphene. Annealing an intercalated sample, representing bi-layer graphene, to a temperature of 850 degrees C. or higher, re-establishes the monolayer graphene with a buffer layer on SiC(0001).
Place, publisher, year, edition, pages
Elsevier , 2011. Vol. 605, no 17-18, 1662-1668 p.
Epitaxial graphene, Hydrogen intercalation, Bi-layer, Buffer layer free, STM, Core-level photoelectron spectroscopy, ARPES, Energy filtered XPEEM
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-70327DOI: 10.1016/j.susc.2010.12.018ISI: 000293937500011OAI: oai:DiVA.org:liu-70327DiVA: diva2:438350
Funding Agencies|Swedish National Energy Administration||2011-09-022011-09-022012-02-06