Fast-Recovery Epitaxial NbN Superconducting Nanowire Single-Photon Detectors with Saturated Efficiency at 1550 nm in Liquid Helium

Fuente: arXiv
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Auteurs principaux: Incalza, Francesca, Castellani, Matteo, Paul, Dip Joti, Simon, Alejandro, Batson, Emma, Mondin, Davide, Medeiros, Owen, Berggren, Karl K.
Format: Preprint
Publié: 2025
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author Incalza, Francesca
Castellani, Matteo
Paul, Dip Joti
Simon, Alejandro
Batson, Emma
Mondin, Davide
Medeiros, Owen
Berggren, Karl K.
author_facet Incalza, Francesca
Castellani, Matteo
Paul, Dip Joti
Simon, Alejandro
Batson, Emma
Mondin, Davide
Medeiros, Owen
Berggren, Karl K.
contents Achieving both high internal efficiency and fast reset times at elevated temperatures remains challenging due to limited understanding of how film properties govern SNSPD performance. We demonstrate that epitaxial NbN films on sapphire enable simultaneous high efficiency and rapid response. We fabricate and characterize SNSPDs based on these films deposited via DC magnetron sputtering on c-cut sapphire. High-quality epitaxial growth preserves a low electron diffusion coefficient and promotes strong electron-phonon coupling, yielding a high critical temperature and efficient hotspot formation in the dirty limit. X-ray diffraction and transmission electron microscopy confirm epitaxial alignment and lattice order. Nanowires of 20 nm width exhibit saturated internal efficiency at 1550 nm wavelength and short reset times at 4.2 K, enabled by lattice matching and high thermal conductance of the sapphire interface. Ab initio modeling reproduces photon count rates, linking device performance quantitatively to film properties such as diffusivity and electron-phonon coupling.
format Preprint
id arxiv_https___arxiv_org_abs_2512_18063
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast-Recovery Epitaxial NbN Superconducting Nanowire Single-Photon Detectors with Saturated Efficiency at 1550 nm in Liquid Helium
Incalza, Francesca
Castellani, Matteo
Paul, Dip Joti
Simon, Alejandro
Batson, Emma
Mondin, Davide
Medeiros, Owen
Berggren, Karl K.
Applied Physics
Achieving both high internal efficiency and fast reset times at elevated temperatures remains challenging due to limited understanding of how film properties govern SNSPD performance. We demonstrate that epitaxial NbN films on sapphire enable simultaneous high efficiency and rapid response. We fabricate and characterize SNSPDs based on these films deposited via DC magnetron sputtering on c-cut sapphire. High-quality epitaxial growth preserves a low electron diffusion coefficient and promotes strong electron-phonon coupling, yielding a high critical temperature and efficient hotspot formation in the dirty limit. X-ray diffraction and transmission electron microscopy confirm epitaxial alignment and lattice order. Nanowires of 20 nm width exhibit saturated internal efficiency at 1550 nm wavelength and short reset times at 4.2 K, enabled by lattice matching and high thermal conductance of the sapphire interface. Ab initio modeling reproduces photon count rates, linking device performance quantitatively to film properties such as diffusivity and electron-phonon coupling.
title Fast-Recovery Epitaxial NbN Superconducting Nanowire Single-Photon Detectors with Saturated Efficiency at 1550 nm in Liquid Helium
topic Applied Physics
url https://arxiv.org/abs/2512.18063