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

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 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 <formula formulatype="inline"><tex Notation="TeX">$(E_{G})$</tex></formula>, 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- <formula formulatype="inline"><tex Notation="TeX">$E_{G}$</tex></formula> region in the channel near the source and a large- <formula formulatype="inline"><tex Notation="TeX">$E_{G}$</tex></formula> region in the middle of the channel, the <emphasis emphasistype="smcaps">on</emphasis>- and <emphasis emphasistype="smcaps">off</emphasis>-state currents ( <formula formulatype="inline"><tex Notation="TeX">$I_{\rm ON}$</tex></formula> and <formula formulatype="inline"><tex Notation="TeX">$I_{\rm OFF}$ </tex></formula>, 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 <formula formulatype="inline"><tex Notation="TeX">$I_{\rm ON}/I_{\rm OFF}$</tex> </formula> ratio of four orders of magnitude can be achieved with a channel length of 10 nm and a drain bias of 0.6 V. </para>