High-performance MoS2 field-effect transistors enabled by chloride doping: Record low contact resistance (0.5 kΩ·µm) and record high drain current (460 µA/µm)

Abstract

In this paper, we report a novel chemical doping technique to reduce the contact resistance (R_c) of transition metal dichalcogenides (TMDs) - eliminating two major roadblocks (namely, doping and high R_c) towards demonstration of high-performance TMDs field-effect transistors (FETs). By using 1,2 dichloroethane (DCE) as the doping reagent, we demonstrate an active n-type doping density > 2×10¹⁹ cm^-3 in a few-layer MoS₂ film. This enabled us to reduce the R_c value to a record low number of 0.5 kΩ·μm, which is ~10×lower than the control sample without doping. The corresponding specific contact resistivity (ρ_c) is found to decrease by two orders of magnitude. With such low R_c, we demonstrate 100 nm channel length (L_ch) MoS₂ FET with a drain current (I_ds) of 460 μA/μm at V_ds = 1.6 V, which is twice the best value reported so far on MoS₂ FETs.