A macroscopic model for vertical graphene-organic semiconductor heterojunction field-effect transistors

Field-effect transistors based on a graphene-organic semiconductor vertical hybrid hold great promise for applications that require a minimal driving voltage, a high current density, and a large transconductance gain. Despite impressive performances reported up to date, their working principles are still not well understood, and therefore a widely applicable functional model is now deemed essential. Here, we report on a physical current-voltage model based on the macroscopic footprints of charge transport and injection associated with the energetic asymmetry within the active diode part of a transistor. The model is composed of separate descriptions of negative and positive drain-biased circuits, which are added to build a single set of equations valid for a broad sweep range. The proposed model is validated by simulating a high-performance fullerene-based device, of which the extracted physical parameters are discussed in detail.