Electrons at Schottky barrier in presence of strong coherent THz radiation

Schottky barrier diodes are widely used as mixers in THz frequency range, due to their low-noise characteristics. However, the understanding of some phenomena behind their operation is still unsatisfactory. In particular, the scaling behavior of optimal current with frequency, combined with distinct manifestations of quantum effects, which had been observed in a series of experiments, still leave a list of unanswered questions. A discussion of the latter questions, along with possible approaches to explain the experimental studies mentioned is presented, and, in particular, the possible role of the energy relaxation effects that are relevant to the phenomena under consideration is discussed.