Ultra-thin TaN Films for Superconducting Nanowire Single-Photon Detectors
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Ultra-thin films of superconducting tantalum nitride are deposited by reactive magnetron sputtering on heated sapphire substrates. The critical temperature T C=10.25 K is reached for films thicker than 10 nm. A superconducting nanowire single-photon detector in the form of a meander line with a width of 110 nm was made from 5 nm thick TaN film. The detector had a transition temperature of 8.3 K and a critical current density of 4 MA/cm2 at 4.2 K. A photon detection efficiency of 20% has been obtained for the detector with a filling factor of 0.55 at wavelengths up to 700 nm.
KeywordsTaN Superconducting thin films Superconducting detectors
The work is supported in part by DFG Center for Functional Nanostructures under sub-project A4.3.
- 7.K.S. Il’in, M. Siegel, A.D. Semenov, A. Engel, H.-W. Hübers, Inst. Phys. Conf. Ser. 181, 2895 (2004) Google Scholar