# 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.

## Key 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.

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Source: https://tomesphere.com/paper/1901.00688