Graphene on the oxidized SiC surface and the impact of the metal intercalation
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2019
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We have performed first-principles calculations of the structural and the electronic properties of graphene (G) adsorbed (i) on the oxidized SiC surface (G/X/SiC, with X ¼ Si2O3, Si2O5, and OH), and (ii) on the
metal (M ¼ Au and Al) intercalated Si2O5 silicate layer, G/(M)Si2O5/SiC. In (i), we focused on the structural
characterization of the oxidized surface, based on a set of simulations of the X-ray absorption spectroscopy (XAS). We found that the XAS features are slightly modified upon the presence of the graphene
layer, which can be attributed to the net charge transfers from the graphene sheet to the oxidized SiC
surface. Such a p-type doping of graphene is larger by the presence of C dangling bonds (DBs), namely G/
Si2O3/and G/Si2O5/SiC(0001). In (ii), we show that (M)Si2O5/SiC is an interesting platform to perform
band engineering based on G/SiC interface. Through a proper combination of surface states and external
electric field, we found the formation of ohmic contacts at the G/(M)Si2O5 interface; namely p-type [ntype] ohmic contact in G/(Au)Si2O5/SiC(0001) [G/(Al)Si2O5/SiC(0001)] with the excess of electrons [holes]
on the metal induced surface states, giving rise to (tuneable) metallic channels localized in the metal
doped silicate monolayer, (M)Si2O5, on top of the SiC surface.
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PADILHA, J. E. et al. Graphene on the oxidized SiC surface and the impact of the metal intercalation. Carbon, Amsterdam, v. 145, p. 603-613, 2019. DOI: 10.1016/j.carbon.2019.01.033. Disponível em: https://www.sciencedirect.com/science/article/pii/S0008622319300338. Acesso em: 9 jul. 2024.