Mohammad Rafiee Diznab1,Erin Johnson1,Jesse Maassen1
Dalhousie University1
Mohammad Rafiee Diznab1,Erin Johnson1,Jesse Maassen1
Dalhousie University1
Transition-metal dichalcogenides (TMDCs), including MoS<sub>2</sub>, have great potential in electronic applications. However, achieving low-resistance metal contacts is a challenge that impacts their performance in nanodevices, due to strong Fermi level pinning and the presence of a tunnelling barrier. As a solution, we explore a strategy utilizing two-dimensional (2D) alkaline-earth sub-pnictide electrenes with a general formula of M<sub>2</sub>X (M = Ca, Sr, Ba; X = N, P, As, Sb) as an intermediate material between the 2D TMDC and metal. Electrenes possess one excess electron per formula unit resulting in the formation of 2D sheets of charge on their surfaces. This charge can be readily donated when interfaced with a TMDC semiconductor, thereby lowering its conduction band below the Fermi level and eliminating Schottky and tunnelling barriers. Density-functional theory calculations were performed on metal-electrene-MoS<sub>2</sub> heterojunctions for all stable M<sub>2</sub>X electrenes, and both Cu and Au metals. To identify the material combinations that provide the most effective Ohmic contact the charge transfer, band structure and electrostatic potential, among other quantities, were analyzed. In all cases, a linear correlation was found between the charge donated to the MoS<sub>2</sub> and the electrene surface charge. The electride Ca<sub>2</sub>N is found to be most promising for achieving an Ohmic metal-MoS<sub>2</sub> contact, due to its high surface charge density.<br/><br/>This research was supported by SRC.