Phosphorene is a single layer of black phosphorous, recently synthesized. Its two-dimentional structure is similar to the carbon-based graphene, however, it is semiconductor compared to graphene with zero gap. So this material has attracted much attention due to its potential usage for electronic or optoelectronic devices. Because of a lone pair of electrons on each phosphorous atom, however, pristine phosphorene may be extremely reactive with air, especially with oxygen, and thus the oxidation of phosphorene would be unavoidable during synthesis and/or fabrication processes unless they were done in a vacuum environment.
Due to the existence of a lone pair of electrons on each P atom, phosphorene can be easily oxidized. At first, we have investigated the structural stability of POx with 0<x<1. For every given 0<x<1 of POx, diverse configurations are considered and optimized to find its equilibrium structure to know whether such a phosphorene oxide can be formed or not.
As x increases in POx, the electronic properties of phosphorene oxides changes. We found an intriguing phenomenon that at around 16% uniaxial tensile strain, PO (with x=1) becomes a metal with a modified Dirac cone at the gamma point in its Brillouin zone.