Interfacial Photogating of Graphene Field‐Effect Transistor for Photosensory Biomolecular Detection

Abstract The photogating effect, induced by a light‐driven gate voltage, modulates the potential energy of the active channel in field‐effect transistors, leading to a high photoconductive gain of these devices. The effect is particularly pronounced in low‐dimensional structures, especially in graphene field‐effect transistors. Along with unusual optical and electrical properties, graphene with ultra‐high carrier mobility and a highly sensitive surface generates a strong photogating effect in the structure, making it an excellent element for detecting light‐sensitive biomolecules. In this work, graphene field‐effect transistor biosensors is demonstrated for the rapid detection of photoactive yellow protein in an aqueous solution under optical illumination. The devices exhibit millisecond‐scale response times and achieve a detection limit below 5.8 fM under blue‐light excitation, consistent with the absorption characteristics of the protein. The photogating effect in graphene field‐effect transistors provides a promising approach for developing high‐performance, light‐sensitive biosensors for biomolecular detection applications.