Band gap engineering in short heteronanotube segments via monovacancy defects

We present a detailed theoretical study of the behaviour of short heterogenous C/BN nanotube segments, notably the effect on band gap of introducing vacancy centres. We have introduced a complete set of band gap calculations, considering a range of different nanotube diameters and chiralities, as well as different arrangements and stoichiometries of C and BN. We have investigated three distinct distributions of BN into CNT segments using density functional theory (DFT) and applying B3LYP/6-31 g(d,p): BN-random distribution, BN-row distribution, and BN-zigzag distribution. We have shown for first time a detailed study for formation energies of carbon monovacancies and how via these defects the band gaps of short heterogeneous CBNNT segments can be reduced. The reduction can reach more than 50% due to carbon vacancy in armchair CBNNTs. The wide varieties of band gaps for carbon vacancy centres may allow the fundamental control needed for designing next-generation electronic components. (C) 2012 Elsevier B. V. All rights reserved.