Low kinetic inductance superconducting MgB2 nanowires with a 130-picosecond relaxation time for single-photon detection applications
Journal article, 2021

Properties of superconducting nanowires set the performance level for Superconducting Nanowire Single Photon Detectors (SNSPD). Reset time in commonly employed large area SNSPDs, 1-10ns, is known to be limited by the nanowire's kinetic inductance to the load impedance ratio. On the other hand, reduction of the kinetic inductance in small area (waveguide integrated) SNSPDs prevents biasing them close to the critical current due to latching into a permanent resistive state. In order to reduce the reset time in SNSPDs, superconducting nanowires with both low kinetic inductance and fast electron energy relaxation are required. In this paper, we report on a study of kinetic inductance in narrow (15-100nm) and long (up to 120m) superconducting MgB2 nanowires made from 5 nm-thick films, offering such combination of properties. Such films were grown using Hybrid Physical Chemical Vapor Deposition, resulting in a critical temperature of 32K, and a switch current density of 5107A/cm2 (at 4.8K). Using microwave reflectometry, we measured a kinetic inductance of Lk0(4.8K)=1.3-1.6 pH/ regardless of the nanowire width, which results in a magnetic field penetration depth of 90 nm. These values are very close to those in pristine MgB2. We showed that after excitations by a 50 fs pulsed laser the reset time in 35nm120m MgB2 nanowires is 130 ps, which is more than a factor of 10 shorter than in NbN nanowires of similar length-to-width ratios. Depending on the bias current, such MgB2 nanowires function as single-, double , or triple- photon detectors for both visible (= 630 nm) and infrared (= 1550 nm) photons, with a dark count rate of <10 cps. Although the apparent photon detection efficiency seems so far to be low, further technological advances (uniform nanowire width, smaller thickness, increasing the switching current closer to the pair-breaking current) may improve this figure of merit.

SNSPD

thin superconducting films

nanowire

single photon detector

magnesium diboride

HPCVD

kinetic inductance

MgB2

Author

Serguei Cherednichenko

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Narendra Acharya

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Evgenii Novoselov

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Vladimir Drakinskiy

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Superconductor Science and Technology

0953-2048 (ISSN) 1361-6668 (eISSN)

Vol. 34 4 044001

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Ultrasnabba singel-foton detektorer

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Fiber Integrated MgB2 Single Photon Detectors

Swedish Research Council (VR), 2020-01-01 -- 2023-12-31.

Areas of Advance

Information and Communication Technology

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Infrastructure

Kollberg Laboratory

Nanofabrication Laboratory

Subject Categories

Other Physics Topics

Nano Technology

Other Electrical Engineering, Electronic Engineering, Information Engineering

Condensed Matter Physics

DOI

10.1088/1361-6668/abdeda

More information

Latest update

4/22/2021