Tunable phase stability and contact resistance of monolayer transition metal dichalcogenides contacts with metal

Monolayer transition metal dichalcogenides/metal (MX₂/metal) based transistors have been widely studied. However, further development is hindered by the large contact resistance between MX₂ and metal contact. In this paper, we demonstrated that interfacial charge transfer between MX₂ and metal is the key for tuning contact resistance. With the lattice misfit criterion applied to screen combination of MX₂s and metals, it has been found out that both phase stability of MX₂ and contact nature between MX₂ and metal will be sensitively affected by interfacial charge transfer. Additionally, we have identified seven MX₂/metal systems that can potentially form zero Schottky barrier contacts utilizing phase engineering. On base of interfacial charge calculations and contact resistance analysis, we have presented three types of MX₂/metal contacts that can be formed with distinguished contact resistance. Our theoretical results not only demonstrate various choice of MX₂/metal designs in order to achieve different amounts of interfacial charge transfer as well as manipulate contact resistance, but also shed light on designing ohmic contacts in MX₂/metal systems.