Superconducting NbTiN Nanowire Single Photon Detectors with Low Kinetic Inductance

Miki, Shigehito; Takeda, M.; Fujiwara, Mikio; Sasaki, Masahide; Otomo, Akira; Wang, Zhen

doi:10.1143/apex.2.075002

Cited by 57 publications

(54 citation statements)

References 18 publications

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“…(Details of the dependence of the transition temperature in NbTiN on the film thickness and growth conditions can be found in Ref. [11].) On the other hand, devices made from NbSi have a much lower value, T c ≈ 2 K, which results in a higher relative detection efficiency for low-energy photons [12].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

et al. 2016

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Superconducting properties of three series of amorphous W x Si 1x films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous W x Si 1x films were deposited by magnetron cosputtering of the elemental source targets onto silicon substrates at room temperature and patterned in the form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperatures, superconducting coherence lengths, magnetic penetration depths, and diffusion constants of electrons in the normal state as functions of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hotspot was analyzed in the framework of a diffusion-based vortex-entry model. We used a two-stage diffusion approach and defined a hotspot size by assuming that the quasiparticles and normal-state electrons have the same diffusion constant. With this definition and these measured material parameters, the hotspot in the 5-nm-thick W 0.85 Si 0.15 film had a diameter of 107 nm at the peak of the number of nonequilibrium quasiparticles. Superconducting properties of three series of amorphous W x Si 1−x films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous W x Si 1−x films were deposited by magnetron cosputtering of the elemental source targets onto silicon substrates at room temperature and patterned in the form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperatures, superconducting coherence lengths, magnetic penetration depths, and diffusion constants of electrons in the normal state as functions of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hotspot was analyzed in the framework of a diffusion-based vortex-entry model. We used a two-stage diffusion approach and defined a hotspot size by assuming that the quasiparticles and normal-state electrons have the same diffusion constant. With this definition and these measured material parameters, the hotspot in the 5-nm-thick W 0.85 Si 0.15 film had a diameter of 107 nm at the peak of the number of nonequilibrium quasiparticles.

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Section: Introductionmentioning

confidence: 99%

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

et al. 2016

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“…With waveguide or optical resonator structure, SNSPD system DE can be higher than 70%. According to equivalent circuit model and former results, a main factor in limiting the counting rate is the kinetic inductance (KI) of the nanowire, which determines the recovery time of SNSPD [19], [28]. NbTiN has superconducting properties and crystal structures similar to those of NbN.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin NbTiN Films with High Ti Composition for Superconducting Nanowire Single Photon Detectors

Jia

Kang

Yang

et al. 2014

IEEE Trans. Appl. Supercond.

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We have fabricated and characterized ultrathin NbTiN films with high Titanium (Ti) composition for applications of superconducting nanowire single photon detectors (SNSPD). An alloy with 47 wt. % Ti and 53 wt. % Nb as the target material is employed. NbTiN thin films with thicknesses ranging from 5 nm to 20 nm are grown onto MgO (100), Si (100) and SiO X -Si substrates by DC magnetron sputtering. The zero resistance superconducting transition temperature (T C0 ) of about 8.8 K has been obtained for the NbTiN film of 8 nm thick on MgO substrate. With twice Ti composition than usual NbTiN film, the lattice mismatch and low resistivity are further improved, which will be more favorable for the performance of SNSPD. The results of the films' structural characterizations by AES, AFM, TEM and XRD are also presented.

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“…In order to achieve both high response speed and high system DE, there seem several approaches. For example, development of high optical coupling technology and adoption of lower KI films such as NbTiN [13] are straightforward way. Array format [23], multi section SNSPD [24], and nano grating structure [25] would be also effective way to solve this issue because they can reduce length of nanowire with keeping the size nanowire area.…”

Section: B Response Speed and Timing Jittermentioning

confidence: 99%

“…We have been systematically developed and investigated a niobium nitride (NbN) superconducting single photon detectors system with Gifford-McMahon (GM) cryocooler, and have improved its performance year by year [10][11][12][13][14][15][16]. In this paper, we describe the fabrication of NbN SNSPD devices, optical packaging technique, development of the SNSPD system with the GM cryocooler, and investigation and improvement of its performances.…”

Section: Introductionmentioning

confidence: 99%

Development of practical superconducting nanowire single photon detector system with high detection efficiency

Miki

Yamashita

Terai

et al. 2011

2011 International Conference on Space Optical Systems and Applications (ICSOS)

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We have developed a practical superconducting nanowire single photon detector (SNSPD) system with our superconducting thin films and devices fabrication, optical coupling packaging, and cryogenic technology. The SNSPD devices were fabricated from high-quality niobium nitride (NbN) ultra-thin films that were epitaxially grown on single-crystal MgO substrates, and optical cavity structure were applied for improvement of photo absorption efficiency. The SNSPD system was developed based on a compact Gifford-McMahon (GM) cryocooler, in which SNSPD can operate continuously at temperature of 2.9 K +/-10 mK with low power consumption without any liquid cryogens. The system detection efficiencies at 1550 nm wavelength (at a 100 Hz dark count rate) were found to be 2.6% for device without optical cavity and 21% for device with optical cavity. The response speed of devices showed maximally 200 MHz with 5 x 5 mm square device, and timing jitter of 100 ps full width at a half maximum (FWHM) was observed.

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Superconducting NbTiN Nanowire Single Photon Detectors with Low Kinetic Inductance

Cited by 57 publications

References 18 publications

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

Ultrathin NbTiN Films with High Ti Composition for Superconducting Nanowire Single Photon Detectors

Development of practical superconducting nanowire single photon detector system with high detection efficiency

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