Nitrogen-doped W0.75Re0.25 Superconducting Nanowire Single Photon Detectors

Nitrogen-doped Tungsten-Rhenium superconducting alloys were recently proposed as a promising material platform for superconducting nanowire single-photon detectors (SNSPDs), offering a favorable balance between high normal state resistivity and tunable superconducting properties. In this work, we report on the fabrication and characterization of SNSPDs based on ultrathin W0.75Re0.25 films deposited by reactive DC magnetron sputtering in a mixed Ar/N2 atmosphere. Meander detectors with 70 nm linewidth exhibit saturated internal detection efficiency up to 1310 nm at 2.5 K, with sub-nanosecond rise times, decay times of the order of a few nanoseconds, and timing jitter of 73.2 ps measured with room temperature amplifiers.