Browsing by Author "Abavare, E.K.K."
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Item A comparative study of the interaction of nickel, titanium, palladium, and gold metals with single-walled carbon nanotubes: A DFT approach(Results in Physics, 2019-03) Kayang, K.W.; Nyankson, E.; Efavi, J.K.; Apalangya, V.A.; Adetunji, B.I.; Gebreyesus, G.; Tia, R.; Abavare, E.K.K.; Onwona-Agyeman, B.; Yaya, A.Interactions between transition metal atoms, nickel, titanium, palladium and gold and (3,3), (4,2), (6,0) and (5,1) carbon nanotubes were studied using first principles calculations. The Fermi energy levels of the carbon nanotubes studied were found to increase during interactions with the transition metal atoms. Amongst the four metals, gold atom was found to have an enhanced interaction with the nanotubes transforming from semiconducting to a conducting tube. Titanium was also found to show similar characteristics to gold only when the atom was placed in the middle of the carbon nanotubes. Nickel and palladium atoms interactions did not affect much the electronic properties of the carbon nanotubes, with some slight changes in the electronic properties at some specific sites of the nanotubes. It is proposed from this study that, the carbon nanotube-metal interactions could be used as a guide to shed light on the electronic properties of such materials which could become promising engineering materials and revolutionize the electronic industry.Item The stability of 3C-SiC(111) on Si(111) thin films: First-principles calculation(Chemical Physics Letters, 2021) Abavare, E.K.K.; Kwakye-Awuah, B.; Nunoo, O.A.; Amoako-Yirenkyire, P.; Gebreyesus, G.; Yaya, A.; Singh, K.We report total energy calculation to elucidate the interface structures between SiC(111) and Si(111) with unequal atom densities due to apparent lattice matching between them. The result shows one stable and three metastable structures for a particular interfacial system with energy differences ranging from 10–52 meV per Å2 for both Si-C and Si-Si interfaces respectively. It was observed that, there is atomic undulation near the Si-C interface pinched at Si substrate. The interface formation energies indicates Si-Si is more favourable compared with Si-C. The electronic structure reveals metallic character due to electron transfer from SiC to Si due to relative electronegativity differences between Si and C atoms.Item Structural and Electronic properties of PVK/C60 Nanoheterostructure interfaces- A DFT Approach(Surfaces and Interfaces, 2020-05-14) Elloh, V.W.; Mishra, A.K.; Dodoo-Arhin, D.; Abavare, E.K.K.; Gebreyesus, G.; Nyankson, E.; Efavi, J.K.; Onwona-Agyeman, B.; Yaya, A.This work seeks to investigate total-energy electronic structure calculation based on density functional theory in the framework of both local density approximations (LDA) and generalized gradient approximation using Perdew, Burke and Ernzerhof (GGA-PBE) form of exchange-correlation with Grimme van der Waals (vdW) correction. Structural and electronic properties as well as density of states of the new class of poly(9-vinylcarbazole)/ C60 (PVK/C60) nanoheterostructures were explored. Three different structural PVK/C60 models were examined and were found to exhibit direct semiconducting behavior base on the two exchange-correlation functionals used, (GGA-PBE & LDA-PZ). The band-gaps calculated with the GGA pseudopotential are 1.276, 1.117 and 0.893 eV, whereas that of the LDA pseudopotentials are, 1.198, 1.010 and 0.749 eV respectively on the three different structural PVK/C60 models. We noted that these bandgaps of the nanoheterostructures can be deliberately tuned leading to promising potential applications in optoelectronics, biomechanics, nanoelectronics, nanoelectro mechanical systems (NEMS), spintronics, opto-electronics and photonic devices manufacturing industry. The calculated structural lattice parameters are in excellent agreement with available experimental dataItem Surface energy of Si(110)- and 3C-SiC(111)-terminated surfaces(Physica Status Solidi (B) Basic Research, 2014) Abavare, E.K.K.; Iwata, J.-I.; Yaya, A.; Oshiyama, A.We perform total-energy electronic-structure calculations based on density functional theory in the framework of the local density approximation to discuss the surface energy convergence of non-polar Si(110)- and polar 3C-SiC(111)-terminated surfaces. Whilst the non-polar surface show monotonic convergence in surface energy, the polar surface is oscillatory. The relaxations of 3C-SiC(111)- and α-6H(0001)-terminated surfaces are very similar; however, the two structures are electronically different due to differences in the relative energetic positions of their dangling bonds. Comparing the energetic positions of the dangling bonds, the calculation revealed that the carbon dangling bond is about 1.32eV lower in energy than that of silicon in the 3C-terminated surface. Again, the presence of these dangling bond states makes both polar and non-polar surfaces show metallic behaviour, as indicated in their respective dispersion curves. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.