Electronic structures and charge carrier mobilities of boron-graphdiyne sheet and nanoribbons

Abstract

Recently, a novel carbon based nanomaterial, boron-graphdiyne (BGDY) was experimentally realized through a bottom-to-up synthetic strategy, which is a π -conjugated structure comprised of all sp -hybridized carbon skeleton and boron heteroatoms in a well-organized two-dimensional (2D) molecular plane, and has been demonstrated to exhibit good semiconducting properties with excellent conductivity. The successful synthesis of this new graphyne material consequently raise the importance of the evaluation of its intrinsic properties, especially the electronic transport properties. In this paper, we firstly investigate the geometry and electronic structure of BGDY sheet based on density functional theory (DFT) calculations, then combined with the Boltzmann transport equation with relaxation time approximation, we predict its charge mobility. It's found that monolayer BGDY is a direct band-gap semiconductor with a moderate bandgap of about 1.26 eV, more importantly, both the electron and hole mobilities are isotopic and high, especially, the electron mobilities can approach as high as 10 5 cm 2 V −1 s −1 . Furthermore, we report the energy band gaps and carrier mobilities of two types of BGYD nanoribbons, called zigzag and armchair nanoribbons. Our numerical calculations show that all the nanoribbons showing semiconducting property and their mobilities are comparable to or even larger than that of BGDY sheet. • The charge mobility of a newly synthesized carbon allotrope, the boron-graphdiyne (BGDY) sheet was predicted based on first-principle calculations. • Monolayer BGDY is semiconductor with a moderate direct bandgap of 1.26 eV, both the electron and hole mobilities are isotopic and high. • All the 1D boron-graphdiyne nanoribbons (BGDYNRs) are found possessing semiconducting property. • The carrier mobilities of BGDYNRs are found comparable to or even larger than that of monolayer BGDY sheet.