DocumentCode :
3278
Title :
Search for Superconductivity in Doped Amorphous Carbon Thin Films
Author :
Pierce, B.T. ; Burke, Jack L. ; Brunke, L.B. ; Bullard, T.J. ; Vier, D.C. ; Haugan, Timothy J.
Author_Institution :
Air Force Res. Lab., Wright-Patterson AFB, OH, USA
Volume :
23
Issue :
3
fYear :
2013
fDate :
Jun-13
Firstpage :
7000205
Lastpage :
7000205
Abstract :
In this paper, we have searched for superconductivity by measuring ohmic resistivity as a function of temperature in amorphous carbon films deposited by pulsed laser deposition and doped by ion implantation with sulfur and phosphorus ions. The doping concentrations were varied from 0.0003 to 4 Vol% for sulfur and 0.0003 to 1 Vol% for phosphorus. Previous efforts have studied doping of carbon-family materials such as highly oriented pyrolytic graphite, diamond-like carbon, and graphite/graphene, which have yielded critical temperatures lower than 20 K. In this study, amorphous carbon films doped with 2.55×1012 ions/cm2 phosphorus concentration showed a distinct change from semiconducting to metallic behavior and a dramatic 10 000-fold decrease in resistivity below 100 K as compared to undoped films. Sulfur-doped films with 2.55 × 1012 ions/cm2 concentration showed up to a 100-fold decrease in resistivity below 100 K as compared to undoped samples. While evidence of superconductivity was not observed, significant improvements in conductivity were noted below 100 K.
Keywords :
amorphous state; carbon; doping profiles; ion implantation; pulsed laser deposition; superconducting thin films; C:P; C:S; carbon-family materials; critical temperatures; diamond-like carbon; doped amorphous carbon thin films; doping concentrations; graphite/graphene; highly oriented pyrolytic graphite; ion implantation; ohmic resistivity; phosphorus ions; pulsed laser deposition; sulfur ions; sulfur-doped films; superconductivity; Annealing; Carbon; Conductivity; Doping; Films; Graphite; Superconductivity; Amorphous; carbon; doping; ion implantation; superconducting materials;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/TASC.2013.2238572
Filename :
6407827
Link To Document :
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