Study of Multiple High-k Dielectric Band Modulated TDGDI GNR FETs

This paper presents a study of graphene nanoribbon (GNR) FETs with different gate dielectrics and/or a combination of high-k and low-k dielectrics in the device. The simulations are done considering the quantum effects within the nonequilibrium function formalism. The use of high-k dielectrics shows improvement in the on-state current (I
on
) as well as in the off-state current (I
off
). The drain-induced barrierlowering parameter also improves with high-k dielectrics. The use of high-k dielectrics at the source-channel junction region improves the performance while there is not much significant improvement in performance of the device with high-k dielectrics at the channel-drain junction only. Further analysis of band structure shows the availability of carriers at lower energy levels for high-k dielectric GNR FETs. The band modulation along the channel is possible with the use of more than one different dielectric material in different regions of the gate oxide along the channel direction. The comparative study of different GNR FETs with two or more dielectrics along the channel region i.e., three different gate dielectric insulators (TDGDI) show improvement in performance as compared to a GNR FET that uses a single dielectric.