Improved p-type Contact to WSe₂ Using a α-RuCl₃Charge-Transfer Interface

A lack of reliable, ohmic contacts at low temperatures has been a barrier to studying the transport properties of semiconducting transition metal dichalcogenide heterostructures, particularly in the monolayer limit. Here we demonstrate a charge-transfer doping scheme, using α-RuCl₃ as a strong electron acceptor, for realizing transparent contact to monolayer WSe₂. Hole densities in the contact region as large as 3.2×10¹³ cm^-2 can be achieved, resulting in contact resistances as low as 1.7 kΩ μm. Device architectures that combine high transparency contacts with independent tunning of the channel density will be discussed.