Possible doping strategies for MoS 2 monolayers: An ab initio study

Density functional theory is used to systematically study the electronic 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…