Crescimento de monocamada de grafeno sobre o ródio(111)

Abstract

This dissertation presents the stages of preparation, characterization, and analysis of the graphene/Rh(111) interface, employing the techniques XPS, LEED, STM, and ARPES. The work was carried out in the SPECS UHV system at the Brazilian Synchrotron Light Laboratory (LNLS). The Rh(111) substrate was prepared through cycles of sputtering and annealing, followed by the growth of graphene using propene under controlled temperature and pressure conditions. The quality of the interface was verified using the aforementioned techniques. XPS results showed two peaks in the C 1s spectrum, indicating two distinct chemical en- vironments for the carbon atoms, associated with different interactions with the substrate. LEED measurements revealed a Moiré structure with a periodicity of 3.3 nm, corroborated by high-resolution STM images, which evidenced structural variations at the interface. ARPES measurements confirmed the presence of the Dirac cone near the K’ point of the Brillouin zone, indicating that the graphene was doped. The Fermi velocity was determined from the linear dispersion plots of the Dirac cone. The results demonstrate that graphene grows in a Moiré-type structure on Rh(111), with differentiated chemical interaction between the graphene and the substrate. This study contributes to the understanding of the electronic and structural properties of this interface.