Improvement of the sensitivity in infrared detectors made of high Tc superconducting films is discussed. Usually these films are grown on a substrate which results in reduced sensitivity due to additional heat capacity of the substrate. A five-fold increase of the noise equivalent power is calculated if free-standing superconducting films are used. A new technique for preparation of thin films of YBa2Cu3Ox without a substrate is also described. The film material is deposited by pulsed laser ablation on a thin carbon film. When the film is annealed in situ in oxygen, the carbon burns off, leaving a free-standing film. The film area can be large as 10X10 mm2 and less than one-half micron thick. They have the correct stoichiometry, the orthorhombic phase and an onset temperature of about 85 K.

Date Published: 1 July 1991
PDF: 5 pages
Proc. SPIE 1477, Superconductivity Applications for Infrared and Microwave Devices II, (1 July 1991); doi: 10.1117/12.45592

Published in SPIE Proceedings Vol. 1477:
Superconductivity Applications for Infrared and Microwave Devices II
Vernon O. Heinen; Kul B. Bhasin, Editor(s)