Effects of extrinsic point defects in phosphorene: B, C, N, O and F Adatoms

TL;DR

This study uses density functional theory to explore how various surface adatoms (B, C, N, O, F) alter the electronic and magnetic properties of phosphorene, revealing potential for property tuning in electronic applications.

Contribution

It provides detailed insights into how specific extrinsic point defects modify phosphorene's electronic structure and magnetic properties, a novel analysis for this 2D material.

Findings

B and C prefer interstitial sites, forming sp2 bonds.

N, O, and F favor surface sites, affecting electronic properties.

B, N, and F induce local magnetic moments.

Abstract

Phosphorene is emerging as a promising 2D semiconducting material with a direct band gap and high carrier mobility. In this paper, we examine the role of the extrinsic point defects including surface adatoms in modifying the electronic properties of phosphorene using density functional theory. The surface adatoms considered are B, C, N, O and F with a [He] core electronic configuration. Our calculations show that B and C, with electronegativity close to P, prefer to break the sp3 bonds of phosphorene, and reside at the interstitial sites in the 2D lattice by forming sp2 bonds with the native atoms. On the other hand, N, O and F, which are more electronegative than P, prefer the surface sites by attracting the lone pairs of phosphorene. B, N and F adsorption will also introduce local magnetic moment to the lattice. Moreover, B, C, N and F adatoms will modify the band gap of phosphorene yielding metallic transverse tunneling characters. Oxygen does not modify the band gap of phosphorene, and a diode like tunneling behavior is observed. Our results therefore offer a possible route to tailor the electronic and magnetic properties of phosphorene by the adatom functionalization, and provide the physical insights of the environmental sensitivity of phosphorene, which will be helpful to experimentalists in evaluating the performance and aging effects of phosphorene-based electronic devices.