Large enhancement of infrared absorption due to trimer comprised of doping-N and S-S divacancies in the imperfect monolayer MoS2: A first-principles study

TL;DR

This study uses first-principles calculations to show that a specific trimer structure in doped monolayer MoS2 significantly enhances infrared absorption, suggesting potential for infrared applications.

Contribution

It reveals the formation of a stable NI-VS-VS trimer in doped MoS2 and links this structure to enhanced infrared absorption, a novel insight into defect engineering for optical properties.

Findings

Stable NI-VS-VS trimer enhances infrared absorption

Doped MoS2 with the trimer shows higher IR absorbance than other configurations

Electronic structure changes due to the trimer explain the absorption enhancement

Abstract

In this study, we systematically study on crystal and electronic structures and optical absorption properties of perfect monolayer MoS2 (M), M with S vacancy (M@SV), M with N doping at S site (M@ND) and M with both S vacancy and N doping at S site (M@V-D) using first-principles method. It is showed that the N atom is tend to located between Mo and S layers, leaving one vacancy at original site, to form interstitial N atom. Thus, the interstitial N atom and the S vacancy make up the NI-VS dimer. We study M@V-D with five atomic configurations and find the most stable structure having the NI-VS-VS trimer. It is showed that the absorbance for the stable M@V-D in the most infrared region is obviously higher than that for the other systems. It is revealed that large enhancement of infrared absorption for the stable M@V-D is mainly attributable to the special electronic structure determined by the crystal structure with the trimer. It is considered that M@V-D could be the promising candidate for infrared materials.