Intrinsic picosecond response times of Y–Ba–Cu–O superconducting photodetectors
| Autor: | Marc Currie, John S. Preston, Roman Sobolewski, S.H. Moffat, C. Williams, Robert A. Hughes, T. Y. Hsiang, M. Lindgren, Philippe M. Fauchet, Frank A. Hegmann |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Applied Physics Letters. 74:853-855 |
| ISSN: | 1077-3118 0003-6951 |
| DOI: | 10.1063/1.123388 |
| Popis: | We report our femtosecond time-resolved measurements on the photoresponse of an epitaxial YBa2Cu3O7−x (YBCO) thin-film photodetector, patterned into a microbridge geometry. By varying the current–voltage biasing conditions between the superconducting and resistive (hot spot) states, we observed transients that correspond to the nonequilibrium kinetic-inductance and the nonequilibrium electron-heating response mechanisms, respectively. The two-temperature model and the Rothwarf–Taylor theory have been used to simulate the measured wave forms and to extract the temporal parameters. The electron thermalization time and the electron–phonon energy relaxation time were determined by the electron temperature rise and decay times, which were found to be 0.56 and 1.1 ps, respectively, in the resistive state. We have also measured the ratio between the phonon and electron specific heats to be 38, which corresponds to a phonon–electron scattering time of 42 ps. No phonon-trapping effect (typical for low-temperature ... |
| Databáze: | OpenAIRE |
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