Three-Dimensional Cold Metals in Realizing Steep-Slope Transistors Based on Monolayer MoS2

Three-dimensional cold metals are explored and applied as a cold source (CS) contact in monolayer (ML) MoS2 FETs to realize sub-60 mV/dec switching. We comprehensively studied the electronic properties of six kinds of cold-metals, cold-metal semiconductor contacts, and the device performance of MoS2 CSFETs by first-principles quantum transport simulations. These cold-metals possess an intrinsic energy gap above the Fermi level and can filter high-energy electrons as a cold electron source. The contact resistances between cold metals and ML-MoS2 are calculated and can be reduced by appropriate doping for high injection currents. Device simulations show that an average subthreshold swing of 20 mV/dec in over five-decades of current and an on-state current over ${5}.{7}\times {10} ^{{2}}\mu \text{A}/\mu \text{m}$ can be achieved in MoS2 CSFETs with cold-metal contacts at ${V}_{\text {D}}$ = 0.5 V and ${I}_{\text {off}}$ = $10^{-{4}}~\mu \text{A}/\mu \text{m}$ . The simulated device performance of MoS2 CSFETs can meet the requirements of IRDS with significantly reduced power dissipation.