Enhancement of the surface reactivity of zigzag boron nitride nanoribbons by chlorine gas decoration: A computational study

Abstract

In this study, we explored the field emission and chlorine sensing mechanisms of zigzag boron nitride nanoribbons (ZBNNRs). First principle calculations were used to investigate the surface reactivity of ZBNNRs within the framework of the density functional theory based on the local density approximation and generalized gradient approximation. Six different possibilities were considered for chlorine-gas termination and adsorption on ZBNNRs. The band gap of the ZBNNRs decreased monotonically as the ribbon width increased. The charges on the functional groups and corresponding bond lengths, i.e., B(N)-X and X-X (Cl-Cl), were dependent on the adsorption sites (B or N edge) and the types of functional groups, but independent of the ribbon width. Chlorine gas (Cl2) induced electrons into the conduction band and their consequent electronic states over the Fermi level enhanced the electrical conductivity. Transmission spectra demonstrated the spin-dependent electron tunneling from the valence band to the conduction band. Charge density analysis indicated the charge trapping behavior of the ZBNNRs. Cl2 introduced excess negative charges onto the active surfaces of the ZBNNRs to enhance their surface reactivity. Therefore, Cl2-decorated ZBNNRs can be employed as Cl2 sensors and they may also be useful in field emission applications.