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.