title: Isoelectronic doping of graphdiyne with boron and nitrogen: stable configurations and band gap modification.
abstract: Graphdiyne, consisting of sp- and sp(2)-hybridized carbon atoms, is a new member of carbon allotropes which has a natural band gap ~1.0 eV. Here, we report our first-principles calculations on the stable configurations and electronic structures of graphdiyne doped with boron-nitrogen (BN) units. We show that BN unit prefers to replace the sp-hybridized carbon atoms in the chain at a low doping rate, forming linear BN atomic chains between carbon hexagons. At a high doping rate, BN units replace first the carbon atoms in the hexagons and then those in the chains. A comparison study indicates that these substitution reactions may be easier to occur than those on graphene which composes purely of sp(2)-hybridized carbon atoms. With the increase of BN component, the band gap increases first gradually and then abruptly, corresponding to the transition between the two substitution motifs. The direct-band gap feature is intact in these BN-doped graphdiyne regardless the doping rate. A simple tight-binding model is proposed to interpret the origin of the band gap opening behaviors. Such wide-range band gap modification in graphdiyne may find applications in nanoscaled electronic devices and solar cells.
authors.affiliation: School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Bu
authors.forename: Mingwen
authors.initials: M
authors.lastname: Zhao
authors.forename: Hongyu
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Xi
authors.forename: Zhenhai
authors.initials: Z
authors.lastname: Wang