Ab-initio study on the possible doping strategies for MoS$_2$ monolayers

TL;DR

This study uses density functional theory to explore doping strategies in MoS$_2$ monolayers, identifying effective dopants and adsorption methods to modulate electronic and magnetic properties for potential electronic applications.

Contribution

It systematically evaluates substitutional and adsorptive doping methods in MoS$_2$, highlighting effective dopants and charge transfer mechanisms for tuning properties.

Findings

Nb is an effective p-type dopant at Mo sites.

Re acts as a donor with low activation energy.

Adsorption of alkali metals induces n-type behavior.

Abstract

Density functional theory is used to systematically study the electronic and magnetic properties of doped MoS$_2$ monolayers, where the dopants are incorporated both via S/Mo substitution or as adsorbates. Among the possible substitutional dopants at the Mo site, Nb is identified as suitable p-type dopant, while Re is the donor with the lowest activation energy. When dopants are simply adsorbed on a monolayer we find that alkali metals shift the Fermi energy into the MoS$_2$ conduction band, making the system n-type. Finally, the adsorption of charged molecules is considered, mimicking an ionic liquid environment. We find that molecules adsorption can lead to both n- and p-type conductivity, depending on the charge polarity of the adsorbed species.