Performance Assessment of Homochiral Carbon Nanotube van der Waals Crystal Transistors

Self-consistent dissipative quantum transport and ab initio density-functional theory (DFT) simulations are used to assess the performance potential of homochiral carbon nanotube (CNT) van der Waals (vdW) crystal FETs. At a gate length required for the upcoming technology nodes, the CNT vdW crystal FETs have a significant performance advantage over both the silicon and monolayer MoS2FETs for high-performance transistor applications. The high packing density of the homochiral CNTs in the CNT vdW crystal boosts the current per channel width, and the interaction between CNTs at the vdW distance only has a small impact on the band structure, which maintains high band-structure-limited velocity and light effective mass. The homochiral CNT vdW crystal FET can achieve a predicted on-current of$\sim {2700}{\,}\mu \textrm {A}/\mu \textrm {m}$at an off-current of$\sim \!{10}^{-2}{\,}\mu \textrm {A}/\mu \textrm {m}$and a power supply voltage of${V}_{\textrm {DD}}={0}.{4}{\,}\text {V}$at a gate length of${12}{\,}\text {nm}$. As the gate length is further scaled down below${10}{\,}\text {nm}$, the CNT vdW crystal FETs, however, suffer from significantly degraded subthreshold swing and large leakage current due to pronounced quantum tunneling effects, while monolayer MoS2has a better performance than both the CNT vdW crystal and silicon FETs at a gate length of${6}{\,}\text {nm}$. For RF applications, the CNT vdW crystal FET outperforms both the silicon and monolayer MoS2FETs in the presence of parasitic capacitance due to its larger carrier velocity and transconductance per channel width.