Characterization of Superconducting Nbn, WSi and MoSi Ultra-Thin Films in Magnetic Field

The system detection efficiency of superconducting nanowire single-photon detectors (SNSPD) has rapidly improved in recent years. In this study, we fabricated NbN, WSi and MoSi ultra-thin films, which are widely used for SNSPD fabrication, employing magnetron sputtering. We characterized the films in the presence of a magnetic field to study the upper critical magnetic field H
_c2
and the anisotropy. According to the results obtained in our experiments, we calculated the coherence length and diffusion coefficient of these films. The knowledge of these parameters will guide the modelling and the interpretation of the different features observed in SNSPD made out of NbN, WSi and MoSi.