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Investigation of Mechanical Properties of Graphene

Rasuli, Reza | 2011

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41279 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Iraji Zad, Azam; Rafii-tabar, Hashem
  7. Abstract:
  8. The unique properties of graphene due to the presence of massless Dirac fermions, high surface to volume ratio, high crystal quality in 2D, and high mechanical strength, recommend it as a promising material for technologies such as nanoelectromechanical systems (NEMS) and nanosensors. Use of graphene in nanodevices is accompanied by induced strains and stresses. Therefore it is important to study the mechanical properties of graphene. In present thesis, we synthesized graphene using both mechanical cleavage of graphite and chemical method. In the chemical method graphene oxide is prepared by oxidation and exfoliation of graphite. The graphene oxide sheets were reduced to prepare graphene sheets and were characterized using X-ray photoelectron spectroscopy, atomic force microscopy (AFM), IR spectroscopy, dynamic light scattering. In addition, we studied the oxidation effect on graphene production from graphite using density functional theory (DFT). Mechanical properties of graphene in the cantilever form was measured using AFM and density functional theory DFT. Using atomic force microscopy and DFT we obtained the mechanical properties such as Young modulus, Hamaker constant and elastic limit of graphene cantilever. Afterwards we studied the effect of mechanical deformation on electronic properties of graphene nanoribbon. Using DFT via Wannier function calculation we explore electronic transport property of strained graphene nano-ribbon via conductance calculation. Results show that band gap of armchair nano-ribbon is strongly dependent on strain and this issue influences its conductance. In addition, conductance calculations show that tensile strain improves sensitivity of graphene sheet to CO molecule
  9. Keywords:
  10. Graphine ; Mechanical Properties ; Strain ; Atomic Force Microscopy (AFM) ; Density Functional Theory (DFT)

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