Open Access Open Access  Restricted Access Subscription Access

Influence of Fabrication Processes on Transport Properties of Superconducting Niobium Nitride Nanowires


Affiliations
1 Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
2 Microelectronics Research Laboratory, Department of Engineering Physics, Delhi Technological University, Bawana Road, Delhi 110 042, India
3 Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
 

Fabrication of niobium nitride (NbN) superconducting nanowires based on focused ion beam (FIB) milling and electron beam lithography (EBL) is presented. The NbN films were deposited using reactive magnetron sputtering. Argon-to-nitrogen ratio turned out to be a crucial factor in synthesizing high quality superconducting NbN. Critical temperatures (Tc) of around 15.5 K were measured for films with a thickness of around 10 nm. Zero-field-cooled magnetization was measured to optimize the superconducting properties of ultra thin NbN films. The transport behaviour was studied using conventional resistance vs temperature and current-voltage characteristics down to 2 K. Effect of gallium contamination on superconducting properties has been discussed. Whereas the various processing steps of standard EBL route do not have any significant impact on the superconducting transition temperature as well as on the transition width of nanowires, there is significant degradation of superconducting properties of nanowires prepared using FIB. This has been attributed to gallium ion implantation across the superconducting channel. Although the effect of gallium implantation may have technological limitations in designing fascinating single photon detector architectures, it provides some interesting low-dimensional superconducting properties.

Keywords

DC Magnetron Sputtering, EBL, FIB, Niobium Nitride, Superconducting Nanostructure, Thin Films.
User
Notifications
Font Size


  • Influence of Fabrication Processes on Transport Properties of Superconducting Niobium Nitride Nanowires

Abstract Views: 462  |  PDF Views: 160

Authors

Manju Singh
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
Rishu Chaujar
Microelectronics Research Laboratory, Department of Engineering Physics, Delhi Technological University, Bawana Road, Delhi 110 042, India
Sudhir Husale
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
S. Grover
Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
Amit P. Shah
Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
Mandar M. Deshmukh
Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
Anurag Gupta
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
V. N. Singh
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
V. N. Ojha
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
D. K. Aswal
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India
R. K. Rakshit
Academy of Scientific and Innovative Research, CSIR-NPL Campus, Dr K.S. Krishnan Marg, New Delhi 110 012, India

Abstract


Fabrication of niobium nitride (NbN) superconducting nanowires based on focused ion beam (FIB) milling and electron beam lithography (EBL) is presented. The NbN films were deposited using reactive magnetron sputtering. Argon-to-nitrogen ratio turned out to be a crucial factor in synthesizing high quality superconducting NbN. Critical temperatures (Tc) of around 15.5 K were measured for films with a thickness of around 10 nm. Zero-field-cooled magnetization was measured to optimize the superconducting properties of ultra thin NbN films. The transport behaviour was studied using conventional resistance vs temperature and current-voltage characteristics down to 2 K. Effect of gallium contamination on superconducting properties has been discussed. Whereas the various processing steps of standard EBL route do not have any significant impact on the superconducting transition temperature as well as on the transition width of nanowires, there is significant degradation of superconducting properties of nanowires prepared using FIB. This has been attributed to gallium ion implantation across the superconducting channel. Although the effect of gallium implantation may have technological limitations in designing fascinating single photon detector architectures, it provides some interesting low-dimensional superconducting properties.

Keywords


DC Magnetron Sputtering, EBL, FIB, Niobium Nitride, Superconducting Nanostructure, Thin Films.

References





DOI: https://doi.org/10.18520/cs%2Fv114%2Fi07%2F1443-1450