Soft X-Ray Single-Photon Detection With Superconducting Tantalum Nitride   and Niobium Nanowires
  We have fabricated ultrafast dark count-free soft X-ray single-photon detectors (X-SNSPDs) from TaN with various conduction path widths, and we compare their properties with corresponding data from a Nb X-SNSPD. The TaN X-SNSPDs offer an improved detector performance regarding device detection efficiency, latching and pulse amplitudes. Wide conduction paths allow for a certain energy-resolving capability in contrast to narrow TaN conduction paths. However, wide paths also limit the detection efficiency at low temperatures, which can be explained within a hot-spot model. 
Kevin Inderbitzin, Andreas Engel and Andreas Schilling (Physics   Institute, University of Z\"urich, Z\"urich, Switzerland)
cond-mat.supr-con cond-mat.mes-hall physics.ins-det