Sb-heterostructure millimeter-wave zero-bias diodes

Zero-bias, square-law detectors based on Sb-heterostructures offer a cost-effective solution for W-band imaging in large array formats. In contrast with Ge backward diodes and planar-doped barrier diodes, Sb-heterostructures have a higher frequency response and are less sensitive to process variables. Here, we demonstrate Sb-based diode detectors in the InAs/AlSb/GaAlSb material system. The large asymmetry in current flow necessary for detection arises from interband tunneling between the InAs and the GaAlSb layers. Current densities are easily controlled by varying either the Al concentration in the GaAlSb or the AlSb thickness. DC and RF characterization of these devices and an estimate of their ultimate frequency performance in comparison with commercially available diodes are presented.