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. (2008). High efficiency NbN nanowire superconducting single photon detectors fabricated on MgO substrates from a low temperature process. Optics Express, 16(5), 3191-3196. DOI: 10.1364/OE.16.003191 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract:We demonstrate high-performance nanowire superconducting single photon detectors (SSPDs) on bN thin films grown at a temperature compatible with monolithic integration. NbN films ranging from 150nm to 3nm in thickness were deposited by dc magnetron sputtering on MgO substrates at 400 • C. SSPDs were fabricated on high quality NbN films of different thickness (7 to 3nm) deposited under optimal conditions. Electrical and optical characterizations were performed on the SSPDs. The highest QE value measured at 4.2K is 20% at 1300nm. Berggren, "Nanowire Single-photon detector with an integrated optical cavity and anti-reflection coating" Opt. Express 14(2), 527-534 (2006). 5. K. Iizuka, K. Matsumaru, T. Suzuki, H. Hirose, K. Suzuki, and H. Okamoto, "Arsenic-free GaAs substrate preparation and direct growth of GaAs/AlGaAs multiple quantum well without buffer layer" J. Cryst. Growth 150(1 -4 pt 1), 13-17 (1995 Gol'tsman, and A. Semenov, "Detection efficiency of large-active-area NbN single-photon superconducting detectors in the ultraviolet to near-infrared range" Appl.

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Well-isolated L10 FePt-SiN x -C nanocomposite films with large coercivity and small grain size Ionized magnetron sputter deposition of hard nanocomposite TiN/amorphous-silicon nitride filmsThe optical and electrical properties of Nb z Si y N x thin films deposited by dc reactive magnetron sputtering have been investigated as a function of the Si content ͑C Si ͒. Optical properties were studied by both specular reflectivity and spectroscopic ellipsometry. Electrical resistivity was measured by the van der Pauw method at room temperature and as a function of the temperature down to 10 K. Both the optical and electrical properties of Nb z Si y N x films are closely related with the chemical composition and microstructure evolution caused by Si addition. For C Si up to 4 at. % the Si atoms are soluble in the lattice of the NbN crystallites. In this compositional regime, the optical and electrical properties show little dependence on the Si content. Between 4 and 7 at. % the surplus of Si atoms segregates at the grain boundaries, builds an insulating SiN x layer, and originates important modifications in the optical and electrical properties of these films. Further increase of C Si leads to the formation of nanocomposite structures. The electrical properties of these films are well described by the grain-boundary scattering model with low probability for electrons to cross the grain boundary. The appearance of the intragranular-insulating SiN x layer and the reduction of the grain size are noticed in the dielectric function mainly as a strong damping of the plasma oscillation.