J. Phys. Colloques
Volume 42, Number C6, Décembre 1981International Conference on Phonon Physics
|Page(s)||C6-317 - C6-319|
J. Phys. Colloques 42 (1981) C6-317-C6-319
LIMITATIONS ON THE USEFULNESS OF METALLIC THIN FILM SEMICONDUCTORS FOR PHONON DETECTIONS.J. Rogers1, C.J. Shaw1 et H.D. Wiederick2
1 Physics Laboratory, University of Kent at Canterbury, Canterbury, Kent, England
2 R.M.C., Kingston, Canada
Ultra-thin metallic films behave essentially as semiconductors. We have explored the use of Ni-Cr devices in this regime for phonon pulse detection. The evaporated films, which were typically ˜ 20 Å thick, were deposited between layers of SiOx on a sapphire substrate. Suitable films had room temperature resistances per square in the range 10 - 13 KΩ and these values increased to 105 - 106 Ω at 1°K. By using very short (25µ) conduction paths in parallel, device resistances were reduced to ˜ 100 Ω at 1°K. We have tested devices down to 0.1°K and two serious problems limit their usefulness : the low temperature resistances are quite non-ohmic for small currents ; the thermal time constants are surprisingly long.