Oxygen defects in phosphorene

TL;DR

This paper investigates how oxygen interacts with phosphorene, revealing stable and metastable forms, their electronic effects, and proposing mechanisms for oxidation and increased hydrophilicity.

Contribution

It provides first-principles insights into oxygen defects in phosphorene, identifying stable and metastable configurations and their electronic properties.

Findings

Oxygen adsorption releases about 2 eV of energy per atom.

Stable oxygen forms are electrically inactive with minor lattice distortions.

Metastable oxygen forms introduce deep electronic levels.

Abstract

Oxygen, invariably present in a normal working environment, is a fundamental cause of the degradation of phosphorene. Using first-principles calculations, we show that for each oxygen atom adsorbed onto phosphorene there is an energy release of about 2 eV. Although the most stable forms of oxygen are electrically inactive and lead only to minor distortions of the lattice, there are a number of low energy metastable forms which introduce deep donor and/or acceptor levels in the gap. We also propose a possible mechanism for phosphorene oxidation and we suggest that dangling oxygen atoms increase the hydrophilicity of phosphorene due to their ability to establish hydrogen bonds.