  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.
