High performance metal-insulator-graphene diodes for radio frequency power detection application

Vertical metal-insulator-graphene (MIG) diodes for radio frequency (RF) power detection are realized using a scalable approach based on graphene grown by chemical vapor deposition and TiO₂ as barrier material. The temperature dependent current flow through the diode can be described by thermionic emission theory taking into account a bias induced barrier lowering at the graphene TiO₂ interface. The diodes show excellent figures of merit for static operation, including high on-current density of up to 28 A cm^-2, high asymmetry of up to 520, strong maximum nonlinearity of up to 15, and large maximum responsivity of up to 26 V^-1, outperforming state-of-the-art metal-insulator-metal and MIG diodes. RF power detection based on MIG diodes is demonstrated, showing a responsivity of 2.8 V W^-1 at 2.4 GHz and 1.1 V W^-1 at 49.4 GHz.