Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

Browse

Has files: NoSubject: search.filters.subject.defects

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Optoelectronic properties of graphene on silicon substrate: Effect of defects in graphene
    (SPIE spie@spie.org, 2015) Javvaji, B.; Ajmalghan, M.; Roy Mahapatra, D.; Rahman, M.R.; Hegde, G.M.
    Engineering of electronic energy band structure in graphene based nanostructures has several potential applications. Substrate induced bandgap opening in graphene results several optoelectronic properties due to the inter-band transitions. Various defects like structures, including Stone-Walls and higher-order defects are observed when a graphene sheet is exfoliated from graphite and in many other growth conditions. Existence of defect in graphene based nanostructures may cause changes in optoelectronic properties. Defect engineered graphene on silicon system are considered in this paper to study the tunability of optoelectronic properties. Graphene on silicon atomic system is equilibrated using molecular dynamics simulation scheme. Based on this study, we confirm the existence of a stable super-lattice. Density functional calculations are employed to determine the energy band structure for the super-lattice. Increase in the optical energy bandgap is observed with increasing of order of the complexity in the defect structure. Optical conductivity is computed as a function of incident electromagnetic energy which is also increasing with increase in the defect order. Tunability in optoelectronic properties will be useful in understanding graphene based design of photodetectors, photodiodes and tunnelling transistors. © 2015 SPIE.
  • No Thumbnail Available
    Item
    Young's modulus of defective graphene sheet from intrinsic thermal vibrations
    (Institute of Physics Publishing helen.craven@iop.org, 2016) Thomas, S.; Mrudul, M.S.; Ajith, A.; Valsakumar, M.C.
    Classical molecular dynamics simulations have been performed to establish a relation between thermally excited ripples and Young's modulus of defective graphene sheet within a range of temperatures. The presence of the out-of-plane intrinsic ripples stabilizes the graphene membranes and the mechanical stability is analyzed by means of thermal mean square vibration amplitude in the long wavelength regime. We observed that the presence of vacancy and Stone-Wales (SW) defects reduces the Young's modulus of graphene sheets. Graphene sheet with vacancy defects possess superior Young's modulus to that of a sheet with Stone-Wales defects. The obtained room temperature Young's modulus of pristine and defective graphene sheet is ∼ 1 TPa, which is comparable to the results of earlier experimental and atomistic simulation studies. © Published under licence by IOP Publishing Ltd.