V Carozo

Publications (2)6.15 Total impact

• Source

  Available from: Indhira Oliveira Maciel

  Article: The use of a Ga+ focused ion beam to modify graphene for device applications.

  B S Archanjo, A P M Barboza, B R A Neves, L M Malard, E H M Ferreira, J C Brant, E S Alves, F Plentz, V Carozo, B Fragneaud, I O Maciel, C M Almeida, A Jorio, C A Achete
  [show abstract] [hide abstract]
  ABSTRACT: In this work, we clarify the features of the lateral damage of line defects in single layer graphene. The line defects were produced through well-controlled etching of graphene using a Ga(+) focused ion beam. The lateral damage length was obtained from both the integrated intensity of the disorder induced Raman D band and the minimum ion fluence. Also, the line defects were characterized by polarized Raman spectroscopy. It was found that graphene is resilient under the etching conditions since the intensity of the defect induced Raman D peak exhibits a dependence on the direction of the lines relative to the crystalline lattice and also on the direction of the laser polarization relative to the lines. In addition, electrical measurements of the modified graphene were performed. Different ion fluences were used in order to obtain a completely insulating defect line in graphene, which was determined experimentally by means of charge injection and electric force microscopy measurements. These studies demonstrate that a Ga+ ion column combined with Raman spectroscopy is a powerful technique to produce and understand well-defined periodic arrays of defects in graphene, opening possibilities for better control of nanocarbon devices.
  Nanotechnology 06/2012; 23(25):255305. · 3.98 Impact Factor
• Article: Identification of graphene crystallographic orientation by atomic force microscopy

  C. M. Almeida, V. Carozo, R. Prioli, C. A. Achete
  [show abstract] [hide abstract]
  ABSTRACT: The direct determination of the crystallographic orientation of graphene sheets was performed using lattice resolution atomic force microscopy images. A graphene sample, micromechanically exfoliated onto a SiO2 substrate showing well defined crystal edges, was imaged in lateral force mode. The lateral force images reveal the periodicity of the graphene hexagonal structure allowing the visualization of the lattice symmetries and determination of the crystal orientation. Crystal edges predominantly formed by zigzag or armchair directions were identified. The nature of the edges was confirmed by Raman spectroscopy.
  Journal of Applied Physics 10/2011; 110(8):086101-086101-3. · 2.17 Impact Factor