| 1. |
- Danilchenko, Boris A., et al.
(author)
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1/f noise and mechanisms of the conductivity in carbon nanotube bundles
- 2011
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In: Carbon. - : Elsevier Ltd. - 0008-6223 .- 1873-3891. ; 49:15, s. 5201-5206
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Journal article (peer-reviewed)abstract
- Experimental results are reported of the investigation of conductivity mechanisms in metallic single-wall carbon nanotube (SWCNT) bundles in a wide temperature range from 4.2 K to 300 K. The temperature dependence of the resistance and noise parameters – the logarithmic slope of the current dependence of noise as well as the normalized current noise – are compared. Remarkable changes in noise characteristics are registered at temperatures typical of the transition from hopping conductivity to Luttinger liquid conductivity and the transition from Luttinger liquid conductivity to diffusion conductivity. In the first transition region, the slope of the normalized noise level of the current changes significantly as a function of temperature. In the region of diffusion conductivity, a stronger variation of the normalized noise level is revealed. These changes in noise properties are correlated with changes in the transport characteristics of SWCNT bundles that allow us to adequately explain the mechanisms of conductivity in the system.
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| 2. |
- Danilchenko, Boris A., et al.
(author)
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High temperature Luttinger liquid conductivity in carbon nanotube bundles
- 2010
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In: Applied Physics Letters. - : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 97:7, s. 072106-
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Journal article (peer-reviewed)abstract
- The conductance and the current-voltage characteristics of metallic single wall carbon nanotube bundles have been measured between 4.2 and 330 K using 10–30 ns electric pulses to avoid overheating. The current-voltage characteristics at different temperatures collapse to a single curve when plotted in the specific coordinates following from the Tomonaga–Luttinger (T–L) liquid concept. Direct evidence is obtained for the existence of a T–L liquid phase up to 190 K and the system shows a transition between the T–L liquid state and a Mott insulating phase below 25 K.
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| 3. |
- Danilchenko, Boris A., et al.
(author)
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Stability of the Tomonaga-Luttinger liquid state in gamma-irradiated carbon nanotube bundles
- 2013
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In: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 25:47, s. 475302-
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Journal article (peer-reviewed)abstract
- We report experimental results for the changes in conductivity of single-wall carbon nanotube bundles when irradiated by Co-60 gamma-rays in various environments. In the current study the samples investigated were irradiated in hermetic cells, either evacuated (0.1 Pa) or filled with hydrogen or deuterium at atmospheric pressure. In situ measurements of the resistance change as a function of irradiation dose at room temperature are presented. It was found that, for all irradiation conditions, the normalized resistance versus irradiation dose demonstrates a logarithmic behaviour. A phenomenological model for the observed dependence is derived. The current-voltage characteristics of the irradiated samples were measured in the temperature range from 4.5 to 300 K using short (10 ns) electric pulses, and the results demonstrate a scaling behaviour. This scaling occurs in the universal coordinates that correspond to the Tomonaga-Luttinger liquid concept. Our results confirm the existence of the Tomonaga-Luttinger liquid phase up to room temperature in carbon nanotubes after gamma-irradiation to a dose of 5 x10(7) rad in vacuum, 1 : 7 x 10(7) rad in hydrogen and 1 : 24 x 10(8) rad in deuterium.
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| 4. |
- Khirunenko, L, et al.
(author)
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Interstitial carbon related defects in low-temperature irradiated Si: FTIR and DLTS studies
- 2005
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In: Solid State Phenomena. - 1012-0394. ; 108-109, s. 261-266
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Journal article (peer-reviewed)abstract
- The evolution of radiation-induced carbon-related defects in low temperature irradiated oxygen containing silicon has been studied by means of Fourier transform infrared absorption spectroscopy (FTIR) and deep level transient spectroscopy (DLTS). FTIR measurements have shown that annealing of interstitial carbon atom C-i, occurring in the temperature interval 260-300 K, results in a gradual appearance of a number of new absorption bands along with the well known bands related to the CiOi complex. The new bands are positioned at 812, 910.2, 942.6, 967.4 and 1086 cm(-1). It has been found that the pair of bands at 910 and 942 cm(-1) as well as another set of the bands at 812, 967.4 and 1086 cm(-1) display identical behavior upon isochronal annealing, i.e. the bands in both groups appear and disappear simultaneously. The disappearance of the first group occurs at T = 285-300 K while the second group anneals out at T = 310-340 K. These processes are accompanied by an increase in intensity of the bands related to CiOi. It is suggested that intermediate states (precursors) are formed upon the transformation from a single (isolated) Ci atom to a stable CiOi defect. The results obtained in DLTS studies are in agreement with the FTIR data and show unambiguously the formation of CiOi precursors with slightly lower activation energy for the hole emission as compare to that for the main CiOi state.
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