  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 at 2.4 GHz and 1.1 V/W at 49.4
GHz.
