A Simulation Study of Graphene-Nanoribbon Tunneling FET With Heterojunction Channel

The device physics and performance of heterojunction (HJ) graphene-nanoribbon (GNR) tunneling field-effect transistors (TFETs) with different designs are investigated in this letter. Due to the width-dependent energy bandgap $(E_{G})$, a single GNR with spatially dependent width naturally yields an HJ structure to improve the device performance of a GNR TFET. By adding a small- $E_{G}$ region in the channel near the source and a large- $E_{G}$ region in the middle of the channel, the on- and off-state currents ( $I_{\rm ON}$ and $I_{\rm OFF}$ , respectively) can be tuned. Last, we have studied the effect of channel length scaling on an HJ GNR TFET, and it has been observed that an $I_{\rm ON}/I_{\rm OFF}$ ratio of four orders of magnitude can be achieved with a channel length of 10 nm and a drain bias of 0.6 V.