Effects of carbon substitution on electronic properties of the ultra-small boron nitride nanotube using density functional theory

Abstract

We perform the local density approximation (LDA) in the density functional theory (DFT) to calculate the electronic properties of carbon-substituted the ultra-small (2,2) armchair boron nitride nanotube (BNNT) structures. In this work, we choose carbon (C) atoms to substitute boron (B) or nitrogen (N) atoms in the pristine structure of the ultra-small (2, 2) armchair BNNT. By substituting one or two atoms (B or N) in the pristine structure with C, the band gap of the ultra-small (2, 2) armchair BNNT (3.01 eV) will reduce or vanish. The existence of C atoms converts the ultra-small (2, 2) armchair BNNT from an insulator nanotube to a semiconductor and a metallic nanotube depend on whether B or N atom sites replaced by C atoms. Furthermore, substituting B atoms with C atoms in the certain sites in the ultra-small (2,2) armchair BNNT pristine structure, will generate that nanotube possesses the n and p semiconductor carrier type.