Self-terminated surface monolayer oxidation induced robust degenerate doping in MoTe2 for low contact resistance.

: We introduce an effective method to degenerately dope MoTe2 by oxidizing its surface into the p-dopant MoOx in oxygen plasma. As a self-terminated process, the oxidation is restricted only in the very top layer, therefore offering us an easy and efficient control. The degenerate p-doping with the hole concentration of 2.5 × 1013 cm-2 can be obtained by applying a ~300 seconds O2 plasma treatment. Using the degenerately doped MoTe2, we demonstrate a record low contact resistance of 0.6 kΩ·μm for MoTe2. Our measurement highlights an excellent stability for the plasma doped MoTe2. The doped characteristics is robust with no significant degradation even after a one-year exposure to the air. The oxygen plasma doping technique is compatible to the conventional semiconductor processes, which can be utilized to realize high performance MoTe2 FETs or tunnel FETs in the future.