▎ 摘　　要

We present a simple design of a field effect transistor based on graphene nanoribbons, taking advantage of the metallic and semiconductor nature of nanoribbons with different widths. Such device could be constructed by using lithography techniques. The conductance of the proposed device is obtained by using the Kubo formula, assuming a strong damping due to the substrate and imperfections of the lattice. By removing the control electrodes, the design could also be used as an electrical resistance.