Superconducting nanowire single photon detectors fabricated from an   amorphous Mo0.75Ge0.25 thin film
  We present the characteristics of superconducting nanowire single photon detectors (SNSPDs) fabricated from amorphous Mo0.75Ge0.25 thin-films. Fabricated devices show a saturation of the internal detection efficiency at temperatures below 1 K, with system dark count rates below 500 counts per second. Operation in a Gifford-McMahon (GM) cryocooler at 2.5 K is possible with system detection efficiencies (SDE) exceeding 20% for SNSPDs which have not been optimized for high detection efficiency. 
V. B. Verma, A. E. Lita, M. R. Vissers, F. Marsili, D. P. Pappas, R.   P. Mirin, and S. W. Nam
cond-mat.supr-con