Possible doping strategies for MoS2monolayers: Anab initiostudy

Abstract

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 the charge polarity of the adsorbed species. DOI: http://dx.doi.org/10.1103/PhysRevB.88.075420 ©2013 American Physical Society