Gayduchenko, I. A., Fedorov, G. E., Stepanova, T. S., Titova, N., Voronov, B. M., But, D., et al. (2016). Asymmetric devices based on carbon nanotubes as detectors of sub-THz radiation. In J. Phys.: Conf. Ser. (Vol. 741, 012143 (1 to 6)).
Abstract: Demand for efficient terahertz (THz) radiation detectors resulted in intensive study of the asymmetric carbon nanostructures as a possible solution for that problem. In this work, we systematically investigate the response of asymmetric carbon nanodevices to sub-terahertz radiation using different sensing elements: from dense carbon nanotube (CNT) network to individual CNT. We conclude that the detectors based on individual CNTs both semiconducting and quasi-metallic demonstrate much stronger response in sub-THz region than detectors based on disordered CNT networks at room temperature. We also demonstrate the possibility of using asymmetric detectors based on CNT for imaging in the THz range at room temperature. Further optimization of the device configuration may result in appearance of novel terahertz radiation detectors.
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Ryzhii, V., Otsuji, T., Ryzhii, M., Leiman, V. G., Fedorov, G., Goltzman, G. N., et al. (2016). Two-dimensional plasmons in lateral carbon nanotube network structures and their effect on the terahertz radiation detection. J. Appl. Phys., 120(4), 044501 (1 to 13).
Abstract: We consider the carrier transport and plasmonic phenomena in the lateral carbon nanotube (CNT) networks forming the device channel with asymmetric electrodes. One electrode is the Ohmic contact to the CNT network and the other contact is the Schottky contact. These structures can serve as detectors of the terahertz (THz) radiation. We develop the device model for collective response of the lateral CNT networks which comprise a mixture of randomly oriented semiconductor CNTs (s-CNTs) and quasi-metal CNTs (m-CNTs). The proposed model includes the concept of the collective two-dimensional (2D) plasmons in relatively dense networks of randomly oriented CNTs (CNT “felt”) and predicts the detector responsivity spectral characteristics exhibiting sharp resonant peaks at the signal frequencies corresponding to the 2D plasmonic resonances. The detection mechanism is the rectification of the ac current due the nonlinearity of the Schottky contact current-voltage characteristics under the conditions of a strong enhancement of the potential drop at this contact associated with the plasmon excitation. The detector responsivity depends on the fractions of the s- and m-CNTs. The burning of the near-contact regions of the m-CNTs or destruction of these CNTs leads to a marked increase in the responsivity in agreement with our experimental data. The resonant THz detectors with sufficiently dense lateral CNT networks can compete and surpass other THz detectors using plasmonic effects at room temperatures.
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Titova, N., Kardakova, A. I., Tovpeko, N., Ryabchun, S., Mandal, S., Morozov, D., et al. (2017). Slow electron–phonon cooling in superconducting diamond films. IEEE Trans. Appl. Supercond., 27(4), 1–4.
Abstract: We have measured the electron-phonon energy-relaxation time, τ eph , in superconducting boron-doped diamond films grown on silicon substrate by chemical vapor deposition. The observed electron-phonon cooling times vary from 160 ns at 2.70 K to 410 ns at 1.8 K following a T -2-dependence. The data are consistent with the values of τ eph previously reported for single-crystal boron-doped diamond films epitaxially grown on diamond substrate. Such a noticeable slow electron-phonon relaxation in boron-doped diamond, in combination with a high normal-state resistivity, confirms a potential of superconducting diamond for ultrasensitive superconducting bolometers.
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Samsonova, A. S., Zolotov, P. I., Baeva, E. M., Lomakin, A. I., Titova, N. A., Kardakova, A. I., et al. (2021). Signatures of surface magnetic disorder in niobium films. IEEE Trans. Appl. Supercond., 31(5), 1–5.
Abstract: We present our studies on the evolution of the normal and superconducting properties with thickness of thin Nb films with a low level of non-magnetic disorder ( kFl≈150 for the thickest film in the set). The analysis of the superconducting behavior points to the presence of magnetic moments, hidden in the native oxide on the surface of Nb films. Using the Abrikosov-Gorkov theory, we obtain the density of surface magnetic moments of 1013 cm −2 , which is in agreement with the previously reported data for Nb films.
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Belosevich, V. V., Gayduchenko, I. A., Titova, N. A., Zhukova, E. S., Goltsman, G. N., Fedorov, G. E., et al. (2018). Response of carbon nanotube film transistor to the THz radiation. In EPJ Web Conf. (Vol. 195, 05012 (1 to 2)).
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