Semi-metallic contacts for n-type transition metal dichalcogenides (TMDs)

Atomically thin transition metal dichalcogenides (TMDs) exhibit many strongly-correlated and exotic electronic phenomena. However electrical transport measurements in TMDs are typically limited by high contact resistances and non-Ohmic behavior of the electrical contacts. Poor electrical contacts to TMDs such as MoSe₂ are due to the formation of a Schottky barrier at the metal/semiconductor interface from work function mismatch and metal-induced gap states (MIGS). Semi-metals such as bismuth and antimony have been demonstrated to achieve record low contact resistances for n-type MoS₂ by suppressing the MIGS at the metal/semiconductor interface. Such reliable electrodes at low temperatures have been lacking for n-type MoSe₂. We fabricate semi-metallic contacts to encapsulated bilayer and monolayer MoSe₂ and present electrical transport measurements at low temperatures down to 2K. We demonstrate that this method of contact engineering can lead to low contact resistances and Ohmic behavior, enabling magnetotransport measurements in MoSe₂.