Records |
Author |
Dube, I.; Jiménez, D.; Fedorov, G.; Boyd, A.; Gayduchenko, I.; Paranjape, M.; Barbara, P. |
Title |
Understanding the electrical response and sensing mechanism of carbon-nanotube-based gas sensors |
Type |
Journal Article |
Year |
2015 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
Volume |
87 |
Issue |
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Pages |
330-337 |
Keywords |
carbon nanotubes, CNT detectors, field effect transistors, FET |
Abstract |
Gas sensors based on carbon nanotube field effect transistors (CNFETs) have outstanding sensitivity compared to existing technologies. However, the lack of understanding of the sensing mechanism has greatly hindered progress on calibration standards and customization of these nano-sensors. Calibration requires identifying fundamental transistor parameters and establishing how they vary in the presence of a gas. This work focuses on modeling the electrical response of CNTFETs in the presence of oxidizing (NO2) and reducing (NH3) gases and determining how the transistor characteristics are affected by gas-induced changes of contact properties, such as the Schottky barrier height and width, and by the doping level of the nanotube. From the theoretical fits of the experimental transfer characteristics at different concentrations of NO2 and NH3, we find that the CNTFET response can be modeled by introducing changes in the Schottky barrier height. These changes are directly related to the changes in the metal work function of the electrodes that we determine experimentally, independently, with a Kelvin probe. Our analysis yields a direct correlation between the ON – current and the changes in the electrode metal work function. Doping due to molecules adsorbed at the carbon-nanotube/metal interface also affects the transfer characteristics. |
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ISSN |
0008-6223 |
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no |
Call Number |
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Serial |
1778 |
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Author |
Gayduchenko, I. A.; Fedorov, G. E.; Ibragimov, R. A.; Stepanova, T. S.; Gazaliev, A. S.; Vysochanskiy, N. A.; Bobrov, Y. A.; Malovichko, A. M.; Sosnin, I. M.; Bobrinetskiy, I. I. |
Title |
Synthesis of single-walled carbon nanotube networks using monodisperse metallic nanocatalysts encapsulated in reverse micelles |
Type |
Journal Article |
Year |
2016 |
Publication |
Chem. Ind. Belgrade |
Abbreviated Journal |
Chem. Ind. Belgrade |
Volume |
70 |
Issue |
1 |
Pages |
1-8 |
Keywords |
carbon nanotubes, CNT, reverse micelles |
Abstract |
We report on a method of synthesis of single-walled carbon nanotubes percolated networks on silicon dioxide substrates using monodisperse Co and Ni catalyst. The catalytic nanoparticles were obtained by modified method of reverse micelles of bis-(2-ethylhexyl) sulfosuccinate sodium in isooctane solution that provides the nanoparticle size control in range of 1 to 5 nm. The metallic nanoparticles of Ni and Co were characterized using transmission electron microscopy (TEM) and atomic-force microscopy (AFM). Carbon nanotubes were synthesized by chemical vapor deposition of CH4/H2 composition at temperature 1000 °С on catalysts pre-deposited on silicon dioxide substrate. Before temperature treatment during the carbon nanotube synthesis most of the catalyst material agglomerates due to magnetic forces while during the nanotube growth disintegrates into the separate nanoparticles with narrow diameter distribution. The formed nanotube networks were characterized using AFM, scanning electron microscopy (SEM) and Raman spectroscopy. We find that the nanotubes are mainly single-walled carbon nanotubes with high structural perfection up to 200 μm long with diameters from 1.3 to 1.7 nm consistent with catalyst nanoparticles diameter distribution and independent of its material. |
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ISSN |
0367-598X |
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no |
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Serial |
1779 |
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Author |
Gayduchenko, I. A.; Fedorov, G. E.; Moskotin, M. V.; Yagodkin, D. I.; Seliverstov, S. V.; Goltsman, G. N.; Yu Kuntsevich, A.; Rybin, M. G.; Obraztsova, E. D.; Leiman, V. G.; Shur, M. S.; Otsuji, T.; Ryzhii, V. I. |
Title |
Manifestation of plasmonic response in the detection of sub-terahertz radiation by graphene-based devices |
Type |
Journal Article |
Year |
2018 |
Publication |
Nanotechnol. |
Abbreviated Journal |
Nanotechnol. |
Volume |
29 |
Issue |
24 |
Pages |
245204 (1 to 8) |
Keywords |
single layer graphene, graphene nanoribbons |
Abstract |
We report on the sub-terahertz (THz) (129-450 GHz) photoresponse of devices based on single layer graphene and graphene nanoribbons with asymmetric source and drain (vanadium and gold) contacts. Vanadium forms a barrier at the graphene interface, while gold forms an Ohmic contact. We find that at low temperatures (77 K) the detector responsivity rises with the increasing frequency of the incident sub-THz radiation. We interpret this result as a manifestation of a plasmonic effect in the devices with the relatively long plasmonic wavelengths. Graphene nanoribbon devices display a similar pattern, albeit with a lower responsivity. |
Address |
Physics Department, Moscow State University of Education, Moscow 119991, Russia. National Research Center 'Kurchatov Institute', 123182, Moscow, Russia |
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ISSN |
0957-4484 |
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Notes |
PMID:29553479 |
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no |
Call Number |
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Serial |
1308 |
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Author |
Gorokhov, G.; Bychanok, D.; Gayduchenko, I.; Rogov, Y.; Zhukova, E.; Zhukov, S.; Kadyrov, L.; Fedorov, G.; Ivanov, E.; Kotsilkova, R.; Macutkevic, J.; Kuzhir, P. |
Title |
THz spectroscopy as a versatile tool for filler distribution diagnostics in polymer nanocomposites |
Type |
Journal Article |
Year |
2020 |
Publication |
Polymers (Basel) |
Abbreviated Journal |
Polymers (Basel) |
Volume |
12 |
Issue |
12 |
Pages |
3037 (1 to 14) |
Keywords |
THz spectroscopy; nanocomposites, percolation threshold, time-domain spectroscopy, time-domain spectrometer, TDS |
Abstract |
Polymer composites containing nanocarbon fillers are under intensive investigation worldwide due to their remarkable electromagnetic properties distinguished not only by components as such, but the distribution and interaction of the fillers inside the polymer matrix. The theory herein reveals that a particular effect connected with the homogeneity of a composite manifests itself in the terahertz range. Transmission time-domain terahertz spectroscopy was applied to the investigation of nanocomposites obtained by co-extrusion of PLA polymer with additions of graphene nanoplatelets and multi-walled carbon nanotubes. The THz peak of permittivity's imaginary part predicted by the applied model was experimentally shown for GNP-containing composites both below and above the percolation threshold. The physical nature of the peak was explained by the impact on filler particles excluded from the percolation network due to the peculiarities of filler distribution. Terahertz spectroscopy as a versatile instrument of filler distribution diagnostics is discussed. |
Address |
Institute of Photonics, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland |
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English |
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ISSN |
2073-4360 |
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Notes |
PMID:33353036; PMCID:PMC7767186 |
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no |
Call Number |
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Serial |
1780 |
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Author |
Gayduchenko, I.; Xu, S. G.; Alymov, G.; Moskotin, M.; Tretyakov, I.; Taniguchi, T.; Watanabe, K.; Goltsman, G.; Geim, A. K.; Fedorov, G.; Svintsov, D.; Bandurin, D. A. |
Title |
Tunnel field-effect transistors for sensitive terahertz detection |
Type |
Journal Article |
Year |
2021 |
Publication |
Nat. Commun. |
Abbreviated Journal |
Nat. Commun. |
Volume |
12 |
Issue |
1 |
Pages |
543 |
Keywords |
field-effect transistors, bilayer graphene, BLG |
Abstract |
The rectification of electromagnetic waves to direct currents is a crucial process for energy harvesting, beyond-5G wireless communications, ultra-fast science, and observational astronomy. As the radiation frequency is raised to the sub-terahertz (THz) domain, ac-to-dc conversion by conventional electronics becomes challenging and requires alternative rectification protocols. Here, we address this challenge by tunnel field-effect transistors made of bilayer graphene (BLG). Taking advantage of BLG's electrically tunable band structure, we create a lateral tunnel junction and couple it to an antenna exposed to THz radiation. The incoming radiation is then down-converted by the tunnel junction nonlinearity, resulting in high responsivity (>4 kV/W) and low-noise (0.2 pW/[Formula: see text]) detection. We demonstrate how switching from intraband Ohmic to interband tunneling regime can raise detectors' responsivity by few orders of magnitude, in agreement with the developed theory. Our work demonstrates a potential application of tunnel transistors for THz detection and reveals BLG as a promising platform therefor. |
Address |
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. bandurin@mit.edu |
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English |
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ISSN |
2041-1723 |
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PMID:33483488; PMCID:PMC7822863 |
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no |
Call Number |
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Serial |
1261 |
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