Effects of Oxygen Contamination on Monolayer GeSe: A computational study

TL;DR

This study uses first-principles calculations to explore how oxygen defects affect the structure and electronic properties of monolayer GeSe, revealing oxidation-induced modifications that could enable new optoelectronic applications.

Contribution

It provides detailed insights into the structural and electronic effects of oxygen contamination on monolayer GeSe, a novel 2D material, highlighting potential for property tuning.

Findings

Oxidation is exothermic and nucleates at germanium sites.

Oxidation causes local deformations and introduces defect states.

Bandgap increases by up to 23% and can change from direct to indirect.

Abstract

Natural oxidation is a common degradation mechanism of both mechanical and electronic properties for most of the new two-dimensional materials. From another perspective, controlled oxidation is an option to tune material properties, expanding possibilities for real-world applications. Understanding the electronic structure modifications induced by oxidation is highly desirable for new materials like monolayer GeSe, which is a new candidate for near-infrared photodetectors. By means of first-principles calculations, we study the influence of oxygen defects on the structure and electronic properties of the single layer GeSe. Our calculations show that the oxidation is an exothermic process, and it is nucleated in the germanium sites. The oxidation can cause severe local deformations on the monolayer GeSe structure and introduces a deep state in the bandgap or a shallow state near the conduction band edge. Furthermore, the oxidation increases the bandgap by up to 23 %, and may induce direct to indirect bandgap transitions. These results suggest that the natural or intentionally induced monolayer GeSe oxidation can be a source of new optoelectronic properties, adding another important building block to the two-dimensional layered materials.