Browsing Research Articles (Physics) by Title

Browsing Research Articles (Physics) by Title

Sort by: Order: Results:

  • Mapasha, Refilwe Edwin; Ukpong, Aniekan M.; Chetty, Nithaya (American Physical Society, 2012-05)
    We present a comparative density functional study of the adsorption of hydrogen on bilayer graphene. Six different exchange-correlation functionals are employed to explore the possible configurations of hydrogen ad- sorption ...
  • Mapasha, Refilwe Edwin; Molepo, Mahlanga P.; Chetty, Nithaya (Elsevier, 2016-05)
    We present a density functional study of various hydrogen vacancies located on a single hexagonal ring of graphane (fully hydrogenated graphene) considering the e ects of charge states and the position of the Fermi level. ...
  • Mapasha, Refilwe Edwin; Chetty, Nithaya (Elsevier, 2010-06)
    We study Li on graphene using the Vienna ab initio Simulation Package employing the projector-augmented wave method within the generalized gradient approximation for the exchange-correlation potential. We give detailed ...
  • Igumbor, Emmanuel; Mapasha, Refilwe Edwin; Meyer, W.E. (Walter Ernst) (Springer, 2017-07)
    The results of an ab initio modelling of aluminium substitutional impurity (AlGe), aluminium interstitial in Ge [IAl for the tetrahedral (T) and hexagonal (H) configurations] and aluminium interstitial-substitutional ...
  • Ouma, C.N.M.; Meyer, W.E. (Walter Ernst) (Elsevier, 2014-04)
    Density functional theory (DFT) within the generalized gradient approximation (GGA) has been used to study the structural and electronic properties of Eu3þ defect complexes in GaN under Ga-rich conditions. Two distinct ...
  • Igumbor, Emmanuel; Ouma, C.N.M.; Webb, Geoffrey; Meyer, W.E. (Walter Ernst) (Elsevier, 2016-01)
    In this work, we present ab-initio calculation results of Ge di-interstitials (I2(Ge)) in the framework of the density functional theory (DFT) using the Heyd, Scuseria, and Ernzerhof (HSE) hybrid functional. The formation ...
  • Igumbor, Emmanuel; Obodo, K.O. (Kingsley Onyebuchi); Meyer, W.E. (Walter Ernst) (Trans Tech Publications, 2016)
    We present detailed calculations of formation and thermodynamics transition state energies of Mgi and Sei interstitial defects in MgSe using generalized gradient approximation (GGA) and local density approximation (LDA) ...
  • Momodu, Damilola Y.; Madito, M.J. (Moshawe); Barzegar, Farshad; Bello, Abdulhakeem; Khaleed, Abubakar A.; Olaniyan, O.; Dangbegnon, Julien K.; Manyala, Ncholu I. (Springer, 2017-03)
    Activated carbon from tree bark (ACB) has been synthesized by a facile and environmentally friendly activation and carbonization process at different temperatures (600, 700 and 800 °C) using potassium hydroxide (KOH) ...
  • Mtangi, Wilbert; Janse van Rensburg, P.J. (Pieter Johan); Diale, M. (Mmantsae Moche); Auret, F.D. (Francois Danie); Nyamhere, Cloud; Nel, Jackie M. (Jacqueline Margot); Chawanda, Albert (Elsevier, 2010-07)
    Current-voltage characteristics of Au/Ni/n-GaN Schottky contacts have been measured in the 60-320 K temperature range. The zero bias barrier height, bo  and ideality factor, n have been studied as a function of temperature. ...
  • Mayimele, M.A.; Auret, F.D. (Francois Danie); Janse van Rensburg, J.P.; Diale, M. (Mmantsae Moche) (Elsevier, 2016-01)
    We report on the analysis of current voltage (I-V) measurements performed on Pd/ZnO Schottky barrier diodes (SBDs) in the 80-320 K temperature range. Assuming thermionic emission (TE) theory, the forward bias I-V ...
  • Rakityansky, S.A.; Elander, N. (Institute of Physics, 2012-03)
    For a two-dimensional quantum-mechanical problem, we obtain a generalized power series expansion of the S-matrix that can be done near an arbitrary point on the Riemann surface of the energy, similar to the standard ...
  • Rakityansky, S.A.; Elander, N. (American Institute of Physics, 2013-12-31)
    A quantum system is considered that can move in N two-body channels with the potentials that may include the Coulomb interaction. For this system, the Jost matrix is constructed in such a way that all its dependencies ...
  • Mtangi, Wilbert; Nel, J.M.; Auret, F.D. (Francois Danie); Chawanda, Albert; Nyamhere, Cloud; Diale, M. (Mmantsae Moche) (Elsevier, 2012-10)
    We report on the studies carried out on hydrogen peroxide treated melt grown, bulk single crystal ZnO samples. Results show the existence of two shallow donors in the as-received ZnO samples with energy levels (37.8 ± ...
  • Venter, Andre; Nyamhere, Cloud; Botha, J.R.; Auret, F.D. (Francois Danie); Janse van Rensburg, J.P.; Meyer, W.E. (Walter Ernst); Coelho, Sergio M.M.; Kolkovsky, V.I. (American Institute of Physics, 2012-03-08)
    Ar plasma etching of n-type (Si doped) GaAs introduces several electron traps (Ec - 0.04 eV, Ec - 0.07 eV, Ec - 0.19 eV, Ec - 0.31 eV, Ec - 0.53 eV, and Ec - 0.61 eV). The trap, Ec - 0.04 eV, labelled E10 and having a ...
  • Bello, Abdulhakeem; Barzegar, Farshad; Momodu, Damilola Y.; Dangbegnon, Julien K.; Taghizadeh, Fatemeh; Fabiane, Mopeli; Manyala, Ncholu I. (Elsevier, 2015-01)
    We present the electrochemical results of highly porous and interconnected carbon material by activation of graphene foam/polyvinyl alcohol-formaldehyde composite material designated as GF/PVA-F. Asymmetric supercapacitor ...
  • Masikhwa, T.M. (Tshifhiwa); Barzegar, Farshad; Dangbegnon, Julien K.; Madito, M.J. (Moshawe); Bello, Abdulhakeem; Momodu, Damilola Y.; Manyala, Ncholu I. (Royal Society of Chemistry, 2016-04)
    VS2 nanosheets as the positive electrode and the activated carbon (AC) as the negative electrode with a 6 M KOH solution as electrolyte were fabricated as an asymmetric supercapacitor. These materials were combined to ...
  • Obodo, K.O. (Kingsley Onyebuchi); Chetty, Nithaya; Obodo, J.T. (Elsevier, 2017-02)
    Using density functional theory within the generalized gradient approximation (GGA), we explore the elastic and electronic properties of monolayer boronitrene containing a double line of substituted carbon atoms. This ...
  • Ouma, C.N.M.; Meyer, W.E. (Walter Ernst) (Elsevier, 2016-06)
    Using both the Perdew–Burke–Ernzerhof (PBE) functional and the hybrid functional of Heyd–Scuseria– Ernzerhof (HSE06), the metastability of the carbon-substitutional–carbon-interstitial (CsCi) defect in silicon has been ...
  • Salagaram, Trisha; Chetty, Nithaya (IOP Publishing Limited, 2013-11-21)
    Most modern scientific research problems are complex and interdisciplinary in nature. It is impossible to study such problems in detail without the use of computation in addition to theory and experiment. Although it is ...
  • Rifkin, Riaan F.; Prinsloo, Linda Charlotta; Dayet, Laure; Haaland, Magnus M.; Henshilwood, Christopher S.; Diz, Enrique Lozano; Moyo, Stanley; Vogelsang, Ralf; Kambombo, Fousy (Elsevier, 2016-02)
    As an unambiguous indication of complex cognitive capacity, representational art presents explicit evidence for modern and symbolic human behaviour. The only examples of African figurative art dating to the Late ...