Bandgap Tuning of a (6,6) Boron Nitride Nanotube by Analyte Physisorption and Application of a Transverse Electric Field: A DFT Study

We report on the feasibility of modulating the electronic bandgap of boron nitride nanotubes (BNNTs) by sidewall physisorption and application of a transverse electric field. In this paper, we extended our analysis to analytes with varying degrees of NO 2 substitution, in comparison to 2,4,6-trinitroluene (2,4,6-TNT), on which we previously reported. Our first-principles calculations suggest that the bandgap of BNNT can be modified by weak adsorption due to the presence of impurity states inside the gap of the host system. The application of a transverse electric field on the adsorbed systems is found to further modify the bandgap, by shifting the unoccupied states of the adsorbents toward the filled states of the host system. Effects of the NO 2 groups on the binding energies of the analytes at the surface of BNNT and on bandgap modification are outlined in this paper.