Hot electron effect in terahertz hybrid devices

We analyse both the direct current and submillimeter pumped current-voltage characteristics of a hybrid superconductor-insulator-superconductor terahertz mixer consisting of a Nb tunnel junction integrated with NbTiN tuning striplines. We find that the presence of the Nb/NbTiN interface gives rise to a hot electron effect. The assumption of an equilibrium electron temperature, as distinct from the phonon temperature, allows a complete understanding of the processes involved. The impact of the hot electron effect on superconducting terahertz detectors is discussed.