Impedance spectroscopy characterization of inkjet-printed graphene/silicon Schottky diodes

The integration of solution-processable two-dimensional (2D) materials into silicon technology is emerging as a promising route toward low-cost and scalable device technologies. Graphene inks deposited on silicon naturally form a Schottky junction, providing the simplest pathway to realize rectifiers compatible with printed and low-temperature processing. While their DC behaviour has been characterized, their dynamic response under alternating signals remains unexplored. Here, we address this gap by performing a systematic impedance spectroscopy study of inkjet-printed graphene/silicon Schottky diodes under different bias conditions. The devices exhibit rectification and bias-controlled cut-off frequency, resulting from bias-dependent resistive and capacitive contributions. The inkjet-printed graphene/silicon Schottky diodes sustain signal modulation up to tens of kilohertz with reproducible bias-dependent features. Our results demonstrate that the dynamic behaviour of such diodes is strongly influenced by the capacitive effect of traps and interfacial processes. This work provides design principles for 2D/silicon devices optimization, highlighting the potential of printed graphene/silicon devices as building blocks for applications ranging from rectifiers and energy harvesters to adaptive sensor interfaces and neuromorphic platforms.