Conference Papers

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

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Subject: search.filters.subject.Graphene

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    Optoelectronic properties of graphene silicon nano-texture
    (Institute of Electrical and Electronics Engineers Inc., 2014) Brahmanandam, J.; Ajmalghan, M.; Abhilash, R.K.; Roy Mahapatra, D.; Rahman, M.R.; Hegde, G.M.
    Graphene on silicon with silicon dioxide quantum dots is a promising opto-electronic material. The optical band gap and the corresponding optical conductivity are estimated using the density functional approach with the combination of molecular dynamics. The regular repeating unit cell of graphene silicon nano-texture is identified using the classical molecular dynamics simulations. Electronic calculations predict the optical band gap is around 0.2 eV and the optical conductivity is identified to be 0.3 times the quantum conductance. © 2014 IEEE.
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    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.
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    Structural analysis of graphene and h-BN: A molecular dynamics approach
    (American Institute of Physics Inc. subs@aip.org, 2016) Thomas, S.; Ajith, A.; Valsakumar, M.C.
    Classical molecular dynamics simulation is employed to analyze pair correlations in graphene and h-BN at various temperatures to explore the integrity of their respective structures. As the temperature increases, the height fluctuations in the out-of-plane direction of both graphene and h-BN are found to increase. The positional spread of atoms also increases with temperature. Thus the amplitude of the peak positions in the radial distribution function (RDF) decreases with temperature. It is found that FWHM of peaks in the RDF of h-BN is smaller as compared to those of graphene which implies that the structure of h-BN is more robust as compared to that of graphene with respect to their respective empirical potential. © 2016 Author(s).
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    Preparation and characterization of nanoparticle blended polymers for thermal energy storage applications
    (American Institute of Physics Inc. subs@aip.org, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.
    This paper is concerned with the comprehensive procedure of preparing, morphological characterization and thermal property evaluation of nanoparticle blended polymer composites. Polymer composites are intended to consecrate the thermal energy storage applications. Linear low-density polyethylene (LLDPE) is incorporated with functionalized graphene with different concentrations (1, 3 and 5%). The morphological study revealed compatibility of polymer composites, at lower concentrations (1-3%,) it shows homogenous dispersion, but above threshold limit the particle distribution is non-homogenous with coarse surface structures. Higher concentration (5%) of nanoparticles emulsifies the molecules and generates micelles between themselves. The thermal conductivity of the polymer composite is significantly enhanced with the reduction of specific heat. At lower concentrations polymer exhibits homogeneous dispersion and the interfacial interaction is comparatively higher, optimal concentration (3%,) of nanoparticle provides favorable results and hence polymer composites with ideal concentration can be utilized for thermal energy storage applications. © 2018 Author(s).