Characterization of NbN/AlN/NbN tunnel junctions

Author

Zhen Wang ; Terai, H. ; Kawakami, A. ; Uzawa, Y.

Author_Institution

Commun. Res. Lab., Minist. of Posts & Telecommun., Kobe, Japan

Volume

9

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

3259

Lastpage

3262

Abstract

We report on tunneling properties and interface structures for high-quality NbN/AlN/NbN tunnel junctions fabricated on ambient temperature MgO substrates. Junction quality and electrical parameters were systematically investigated in a very wide range for current density. The junctions show a very good junction quality with a high gap voltage, large I/sub c/R/sub N/ product, and large R/sub sg//R/sub N/ ratio as the current density varied from 100 A/cm/sup 2/ to above 100 kA/cm/sup 2/. The average barrier heights of the NbN/AlN/NbN tunnel junctions are calculated from the barrier thickness dependence of the critical current density. We found that the current density has two distinct types of dependency on the AlN barrier thickness, corresponding to two average barrier heights in different regions for the current density.

Keywords

aluminium compounds; critical current density (superconductivity); niobium compounds; superconductive tunnelling; MgO substrate; NbN-AlN-NbN; NbN/AlN/NbN tunnel junction; barrier height; critical current density; electrical parameters; interface structure; tunneling properties; Current density; Current measurement; Electrodes; Josephson junctions; Sputtering; Substrates; Superconducting epitaxial layers; Temperature; Tunneling; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.783724

Filename

783724