Is silicene stable in air? -- First principles study of oxygen adsorption and dissociation on silicene

TL;DR

This study uses first-principles calculations to show that pristine silicene readily adsorbs and dissociates oxygen, indicating it is unstable in air and likely to form Si-O compounds.

Contribution

It provides the first detailed atomic-level insight into oxygen interaction with silicene, revealing its instability in air due to barrierless dissociation.

Findings

Oxygen adsorbs and dissociates easily on silicene

Dissociated oxygen atoms have limited mobility

Silicene likely forms Si-O compounds in air

Abstract

The oxygen adsorption and dissociation on pristine silicene surface are studied by use of first-principles in this letter. The oxygen adsorption and dissociation on pristine silicene surface are studied by use of first-principles in this letter. It is found that the pristine silicene is not stable in air because the oxygen molecule can be easily adsorbed and dissociated into two O atoms without overcoming any energy barrier on pristine silicene surface. In addition, dissociated oxygen atoms are relatively difficult to migrate on or desorbed from pristine silicene surface, leading to poor mobility of oxygen atom. As a result, silicene would be changed into Si-O compounds in air. The work will be helpful to reveal the detail of the interaction between oxygen molecules and pristine silicene surface, especially helpful to understand the stability of silicene in air.