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Title: Amorphous molybdenum silicon superconducting thin films

Amorphous superconductors have become attractive candidate materials for superconducting nanowire single-photon detectors due to their ease of growth, homogeneity and competitive superconducting properties. To date the majority of devices have been fabricated using W{sub x}Si{sub 1−x}, though other amorphous superconductors such as molybdenum silicide (Mo{sub x}Si{sub 1−x}) offer increased transition temperature. This study focuses on the properties of MoSi thin films grown by magnetron sputtering. We examine how the composition and growth conditions affect film properties. For 100 nm film thickness, we report that the superconducting transition temperature (Tc) reaches a maximum of 7.6 K at a composition of Mo{sub 83}Si{sub 17}. The transition temperature and amorphous character can be improved by cooling of the substrate during growth which inhibits formation of a crystalline phase. X-ray diffraction and transmission electron microscopy studies confirm the absence of long range order. We observe that for a range of 6 common substrates (silicon, thermally oxidized silicon, R- and C-plane sapphire, x-plane lithium niobate and quartz), there is no variation in superconducting transition temperature, making MoSi an excellent candidate material for SNSPDs.
Authors:
; ;  [1] ;  [2]
  1. Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB3 0FS UK (United Kingdom)
  2. School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT (United Kingdom)
Publication Date:
OSTI Identifier:
22492290
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 8; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CONCENTRATION RATIO; LITHIUM COMPOUNDS; MOLYBDENUM; MOLYBDENUM SILICIDES; NANOWIRES; NIOBATES; PHOTONS; QUARTZ; SAPPHIRE; SILICON; SPUTTERING; SUBSTRATES; SUPERCONDUCTORS; THIN FILMS; TRANSITION TEMPERATURE; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION