Electronic structure tuning via surface modification in semimetallic nanowires

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Sanchez-Soares, Alfonso
O'Donnell, Conor
Greer, James C.
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Electronic structure properties of nanowires (NWs) with diameters of 1.5 and 3 nm based on semimetallic α − Sn are investigated by employing density functional theory and perturbative GW methods. We explore the dependence of electron affinity, band structure, and band-gap values with crystallographic orientation, NW crosssectional size, and surface passivants of varying electronegativity. We consider four chemical terminations in our study: methyl (CH3), hydrogen (H), hydroxyl (OH), and fluorine (F). Results suggest a high degree of elasticity of Sn-Sn bonds within the Sn NWs’ cores with no significant structural variations for nanowires with different surface passivants. Direct band gaps at Brillouin-zone centers are found for most studied structures with quasiparticle corrected band-gap magnitudes ranging from 0.25 to 3.54 eV in 1.5-nm-diameter structures, indicating an exceptional range of properties for semimetal NWs below the semimetal-to-semiconductor transition. Band-gap variations induced by changes in surface passivants indicate the possibility of realizing semimetal-semiconductor interfaces in NWs with constant cross-section and crystallographic orientation, allowing the design of novel dopant-free NW-based electronic devices.
Nanowires , NW-based electronic devices , Electronic structure properties , Elasticity
Sanchez-Soares, A., O'Donnell, C. and Greer, J. C. (2016) 'Electronic structure tuning via surface modification in semimetallic nanowires', Physical Review B, 94(23), 235442. doi:10.1103/PhysRevB.94.235442
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