Current responsivity of semiconductor superlattice THz-photon detectors

The current responsivity of a semiconductor superlattice THz- photon detector is calculated using an equivalent circuit model which takes into account the finite matching efficiency between a detector antenna and the superlattice in the presence of parasitic losses. Calculations performed for currently available superlattice diodes show that both the magnitudes and the roll-off frequencies of the responsivity are strongly influenced by an excitation of hybrid plasma-Bloch oscillations which are found to be eigenmodes of the system in the THz- frequency band. The expected room temperature values of the responsivity (2-3 A/W in the 1-3 THz- frequency band) range up to several percents of the quantum efficiency e/h omega of an ideal superconductor tunnel junction detector. Properly designed semiconductor superlattice detectors may thus demonstrate better room temperature THz- photon responsivity than conventional Schottky junction devices. (C) 1999 American Institute of Physics. [S0021-8979(99)03807-4].