Theoretical investigation of quantum capacitance in the functionalized MoS${}_2$-monolayer

Abstract

In this work, we investigated the electronic structure and the quantum capacitance of the functionalized MoS${}_2$ monolayer. The functionalizations have been done by using different ad-atom adsorption on Mo$S_2$ monolayer. Density functional theory calculations are performed to obtain an accurate electronic structure of ad-atom doped MoS${}_2$ monolayer with a varying degree of doping concentration. The quantum capacitance of the systems was subsequently estimated. A marked quantum capacitance above 200 $\mu$F/cm${}^2$ has been observed. Our calculations show that the quantum capacitance of MoS${}_2$ monolayer is significantly enhanced with substitutional doping of Mo with transition metal ad-atoms. The microscopic origin of such enhancement in quantum capacitance in this system has been analyzed. Our DFT-based calculation shows that generation of new electronic states at the proximity of the band-edge and the shift of Fermi level caused by the ad-atom adsorption results in a very high quantum capacitance in the system.

7 pages, 12 figures and 4 tables