Single photon detection performance of highly disordered NbTiN thin films

TL;DR

This study explores the performance of highly disordered NbTiN superconducting nanowire single photon detectors, demonstrating high efficiency and low jitter, with potential for infrared photon detection.

Contribution

It provides new insights into how composition affects the detection performance of disordered NbTiN SNSPDs, highlighting their suitability for infrared applications.

Findings

Maximal transition temperature at Nb content xNb~0.65

Detection efficiency of approximately 92% at 1550 nm

Timing jitter around 26 ps

Abstract

We experimentally investigated the detection performance of highly disordered NbxTi1-xN based superconducting nanowire single photon detectors (SNSPDs). The dependence on the composition of the transition temperature Tc for NbxTi1-xN films show a dome-like behavior on the Nb content, with a maximal Tc at xNb~0.65 , and the Nb0.65Ti0.35N films also combine relatively large sheet resistance and intermediate residual resistivity ratio. Moreover, 60-nm-wide and 7-nm-thick Nb0.65Ti0.35N nanowires show a switching current as high as 14.5 uA, and saturated intrinsic detection efficiency with a plateau of more than 2 uA 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 NbxTi1-xN films are promising for fabricating SNSPDs for near- and middle-infrared single photons with high detection efficiency and low timing jitter.