Single photon detection performance of highly disordered NbTiN thin films

Abstract

We experimentally investigated the detection performance of highly disordered based superconducting nanowire single photon detectors (SNSPDs). The dependence on the composition of the transition temperature for films show a dome-like behavior on the Nb content, with a maximal at and the films also combine relatively large sheet resistance and intermediate residual resistivity ratio. Moreover, 60-nm-wide and 7-nm-thick nanowires show a switching current as high as 14.5 μA, and saturated intrinsic detection efficiency with a plateau of more than 2 μA at 2.4 K. Finally, the corresponding SNSPDs on an alternative SiO2/Ta2O5 dielectric mirror showed a system detection efficiency of approximately 92% for 1550 nm photons, and the timing jitter is around 26 ps. Our results demonstrate that the highly disordered films are promising for fabricating SNSPDs for near- and middle-infrared single photons with high detection efficiency and low timing jitter.