Print Email Facebook Twitter Optimizing the stoichiometry of ultrathin NbTiN films for high-performance superconducting nanowire single-photon detectors Title Optimizing the stoichiometry of ultrathin NbTiN films for high-performance superconducting nanowire single-photon detectors Author Zichi, Julien (KTH Royal Institute of Technology) Chang, J. (TU Delft ImPhys/Optics) Steinhauer, Stephan (KTH Royal Institute of Technology) Von Fieandt, Kristina (Uppsala University) Los, J.W.N. (Single Quantum B.V.) Visser, G.J. (Single Quantum B.V.) Kalhor, N. (Single Quantum B.V.) Esmaeil Zadeh, I.Z. (TU Delft ImPhys/Optics) Zwiller, Val (KTH Royal Institute of Technology; Single Quantum B.V.) Date 2019 Abstract The requirements in quantum optics experiments for high single-photon detection efficiency, low timing jitter, low dark count rate and short dead time have been fulfilled with the development of superconducting nanowire single-photon detectors. Although they offer a detection efficiency above 90%, achieving a high time resolution in devices made of amorphous materials is a challenge, particularly at temperatures above 0.8 K. Devices made from niobium nitride and niobium titanium nitride allow us to reach the best timing jitter but, in turn, have stronger requirements in terms of film quality to achieve a high efficiency. Here we take advantage of the flexibility of reactive co-sputter deposition to tailor the composition of NbxTi1-xN superconducting films and show that a Nb fraction of x = 0.62 allows for the fabrication of detectors from films as thick as 9 nm and covering an active area of 20 µm, with a wide detection saturation plateau at telecom wavelengths and in particular at 1550 nm. This is a signature of an internal detection efficiency saturation, achieved while maintaining the high time resolution associated with NbTiN and operation at 2.5K. With our optimized recipe, we reliably fabricated detectors with high critical current densities reaching a saturation plateau at 1550 nm with 80% system detection efficiency and with a FWHM timing jitter as low as 19.5 ps. To reference this document use: http://resolver.tudelft.nl/uuid:9cc51e0f-6994-497e-9887-345c3c3d0c1d DOI https://doi.org/10.1364/OE.27.026579 ISSN 1094-4087 Source Optics Express, 27 (19), 26579-26587 Part of collection Institutional Repository Document type journal article Rights © 2019 Julien Zichi, J. Chang, Stephan Steinhauer, Kristina Von Fieandt, J.W.N. Los, G.J. Visser, N. Kalhor, I.Z. Esmaeil Zadeh, Val Zwiller, More Authors Files PDF oe_27_19_26579.pdf 3.76 MB Close viewer /islandora/object/uuid:9cc51e0f-6994-497e-9887-345c3c3d0c1d/datastream/OBJ/view