INVESTIGADORES
BONETTO fernando Jose
congresos y reuniones científicas
Título:
Graphene formation by electron beam induced deposition.
Autor/es:
C. SILVA; F. BONETTO; S. MONTORO; L. BENITEZ; A. CANDIA; M. PASSEGGI; R. VIDAL
Lugar:
Aracaju, Brasil
Reunión:
Encuentro; Autumn Meeting of the Brazilian Physical Society; 2019
Resumen:
We analyze the carbonaceous ¯lms grown on Cu(111) by means of electron beam induced deposition (EBID) using ethylene as a precursor gas. The study was performed for two different precursor gas pressures in an ultra-high vacuum chamber, and two substrate temperatures. In the whole set of experiments, we started with a clean Cu(111) sample and keeping constant the other parameters involved in the process such as the energy and current density of the electron beam. To characterize the ¯lms during the formation process we used AES(Auger Electron Spectroscopy) and EELS (Electron Energy Loss Spectroscopy). These techniques allow us to determine the relative amount of carbon deposited on the surface, and to establish the type of carbon atoms bonds at the surface. We found that there is no in°uence of the substrate temperature on the amount of carbon deposited at low exposures. However, at high ethylene exposures, the amount of carbon deposited decreases if the substrate temperature increases. The analysis of the C(KLL) line shape of the Auger spectra measured after each deposition demonstrates that the chemical structure of the surface carbon compounds is the same for all the samples grown by EBID. The rate of carbon deposition is constant for the first 4000 L, regardless of ethylene pressure (P) and substrate temperature (T). Above this level of exposure, some dependence with P and T is observed. Both, AES and EELS spectra indicate a majority of sp2 bonds in the carbon structures formed on the surface, consistent with the formation of a graphitic compound (or graphene). Scanning tunneling microscopy (STM) and Raman spectroscopy were used as complementary but decisive techniques to assess the structure of the obtained films. From all the results obtained we can conclude that the carbonaceous films are formed by patches of defective few layer (1 or 2) graphene.