Electronic and optical properties of Mn impurities in ultra-thin ZnO nanowires: insights from density-functional theory

TL;DR

This study uses density-functional theory to explore how surface effects like hydrogen adsorption and oxygen vacancies influence the electronic and magnetic properties of Mn-doped ZnO nanowires, revealing surface segregation and site preferences.

Contribution

It provides new insights into the atomic and electronic structure of Mn-doped ZnO nanowires, highlighting the impact of surface chemistry on Mn incorporation and magnetic properties.

Findings

Mn atoms segregate to the surface without passivation

Hydrogen adsorption favors Mn incorporation at inner sites

Oxygen vacancies affect charge localization but not magnetic moments

Abstract

In this work we have employed density-functional theory with hybrid functionals to investigate the atomic and electronic structure of bare and hydrogenated Mn doped ZnO nanowires with small diameter. We determine changes in magnetic and electronic structure of Mn-doped ZnO nanowires due to surface effects, such as hydrogen adsorption on the surface, presence of oxygen vacancies and dangling bonds. In the absence of passivation on the nanowire surface, the manganese atoms segregate to the surface, whereas under hydrogen adsorption the incorporation of Mn is energetically more favourable at inner sites. The presence of additional oxygen vacancies does not produce signficant changes in magnetic moments, although it produce significant changes in charge localization.