The electron-phonon relaxation time in thin superconducting titanium nitride films

Abstract

We report on the direct measurement of the electron-phonon relaxation time, ! eph , in disordered TiN films. Measured values of ! eph are from 5.5 ns to 88 ns in the 4.2 to 1.7 K temperature range and consistent with a T -3 temperature dependence. The electronic density of states at the Fermi level N 0 is estimated from measured material parameters. The presented results confirm that thin TiN films are promising candidate-materials for ultrasensitive superconducting detectors.

Electron–Phonon Energy Relaxation Time in Thin Strongly Disordered Titanium Nitride Films

“…Therefore it is important to measure in the normal state. We have recently reported results on the electron-phonon interaction in thin magnetron-sputtered TiN films [20]. The measured values of τ eph are in the range from 5.5 ns at 4.2 K and to 88 ns at 1.7 K and correspond to T -3 temperature dependence, as reported in [20].…”

“…We have recently reported results on the electron-phonon interaction in thin magnetron-sputtered TiN films [20]. The measured values of τ eph are in the range from 5.5 ns at 4.2 K and to 88 ns at 1.7 K and correspond to T -3 temperature dependence, as reported in [20]. The recent extensive study of material properties of the similarly sputterdeposited TiN films shows that the films have a nonuniform oxygen incorporation which strongly influences film properties and limits the use of sputtered films in large circuits [11].…”

Relaxation of the resistive superconducting state in boron-doped diamond films

“…As argued above we interpret this time as the energy-relaxation time between the electron and the phonon system. In previous experiments, such as for TiN [15], we find that it obeys a power law with the exponent p = 3. Here we find clearly the exponent p = 2 (Fig.…”

“…Application of a perpendicular magnetic field brings the film into a resistive state at various temperatures, which makes it possible to measure the energyrelaxation rate as a function of temperature, although over a limited range of temperatures. The technique has been applied to various materials, usually providing different temperature dependences of the relaxation rate, for example T 2 in Nb film [13], T 1.6 in NbN [14], and T 3 in TiN [15] and in NbC [16].…”

Design and Characterisation of Titanium Nitride Subarrays of Kinetic Inductance Detectors for Passive Terahertz Imaging

“…Study of electrodynamic response shows that the behaviour of TiN films deviates from Mattis–Bardeen theory [10] and temperature dependence of microwave-probed relaxation time has weaker temperature dependence than predicted in Kaplan theory [9]. At the same time, relaxation times measured in both sputtered and ALD TiN films are close to show similar values and temperature dependencies [13, 14]. Although TiN exhibits anomalous behaviour, it remains promising for applications in high background THz detection.…”