Modelling Logic Gates Design Using Pyrrole Based Single Molecular Field Effect Transistor

In this work, we demonstrated the logic gate design using pyrrole based single molecular field effect transistor (FET) for the first time. The semi empirical quantum transport method, which is applying non-equilibrium Green’s function (NEGF) in combination with self-consistent extended Huckel theory (SCEHT), has been adopted to study the charge transport characteristics of a modeled device. By using transmission characteristics T(E), current-voltage Isd-Vsd characteristics and molecular projected self-consistent Hamiltonian (MPSH) states, we systematically analysed charge transport characteristics of the pyrrole based single molecular FET. Theoretical results indicate that the external transverse gate bias can effectively tune the electronic transport properties of the molecular devices to a greater extent. The results exhibit that, with respect to the applied transverse gate bias Vg, the magnitude of the source-drain current Isd varies over more than five times under the same source-drain bias Vsd. The gate controlled NDR feature, which is observed at the different Vsd bias, originates from the changes in the coupling degree between the molecular orbitals and electrodes. Finally, we demonstrate the application of using pyrrole based single molecular FET to realize five basic logic gates. The key feature of the suggested design is the opportunity of realizing different logic gates with just one molecular unit transistor.