▎ 摘　　要

The effect of 2-D electrostatic environment on the device performance of ultimately thin-body tunneling field-effect transistors (UTB-TFETs) using graphene nanoribbons (GNRs) is investigated by varying the gate-oxide thickness and insulating material with different dielectric constants (k). Compared to Si TFETs with different body thicknesses, the atomic-layer-thick structure enhances the lateral fringing fields at the source-channel interface, resulting in a lower ON-state current in GNR TFETs with high-k oxide as compared to the low-k variant of the same thickness. Low-k spacers are therefore essential to counter this effect and reap the benefits of high-k dielectrics in improving the device performance of UTB-TFETs.