Quantum Transport and Photon-Assisted Andreev Reflection in Superconductor–Semiconductor Interface

We have investigated the quantum transport through the Superconductor–Semiconductor mesoscopic interface in the presence of an external radiation field. The current spectrum is analyzed as a function of the frequency and the temperature. The current–voltage (I–V) characteristics were found to be very sensitive to the photon frequency. Additionally, photon-assisted transport in our system is very robust: The one-photon channel remains up to lowtemperature, which implies that these structures support gain at THz frequencies even at 9 K. The resonances sit on a background current which it is deeply modified, as a result of photon assisted multiple Andreev reflections. The results render rigid support for the full quantum theory of transport between two superconductors based on the idea of Andreev bound states.