Doping Strategies for Monolayer MoS2 via Surface Adsorption: A Systematic Study

Using density functional theory calculations, we have systematically explored the effect of surface adsorption of different atoms on the electronic properties of monolayer molybdenum disulfide (MoS2). We have chosen a few representative members from each group in the periodic table, ranging from alkali metals (group I) to halogens (group VII), and calculated the electronic band structure of the adatomMoS(2) system for the most energetically stable location of the adatom adsorbed on MoS2. The calculated value of charge transfer from the adsorbed adatom to MoS2 and resultant shifting of the Fermi level to the conduction band suggest that the group I (Li, Na, K) and group II metals (Mg, Ca) are the most effective adatoms to enhance the n-type mobile carrier density in MoS2. Our calculation is in good agreement with the experimental observation for K [Nano Lett. 2013, 13, 1991].