A new approach to study the effect of generation rate on drain-source current of bilayer graphene transistors

This paper presents a new approach to study the effect of impact ionization on the current of bilayer graphene field effect transistors. Analytical models for surface potential and current together with a Monte Carlo approach which include the edge effect scattering are used to calculate the current and generation rate in bilayer graphene transistors due to ionization. FlexPDE simulation is also employed for verification of surface potential modeling. Using the approach, the profile of generation rate, surface potential and current are plotted with respect to several structural parameters. We have shown that ignoring this effect in the modeling will result in an error of up to 10 % for a typical 30 nm bilayer graphene field effect transistor. As a result, we conclude that any analytical study ignoring the ionization is incomplete for bilayer graphene field effect transistors. The model presented here can be applied in optimization of photo detectors based on graphene. (author)