Lattice-matched p+-GaAsSb/i-InAlAs/n-InGaAs zero-bias backward diodes for millimeter-wave detectors and mixers

A high voltage sensitivity (β_v) of 2100 V/W at 94 GHz was achieved at zero bias using backward diodes that are based on a type II heterojunction of GaAsSb/InGaAs, which was lattice-matched to an InP substrate. The impedance-matched voltage sensitivity (β_v,opt) of a circular mesa diode with a diameter of 1.6 μm was estimated to be 20,000 V/W. A large curvature coefficient (γ) of -35 V^-1 was obtained at zero bias. Epitaxial grown lattice-matched backward diodes on the InP substrate have fewer defects and smooth surfaces, indicating that the devices can be stably reproduced.