| 71. |
- Sveningsson, Martin, 1977, et al.
(författare)
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Field emission from multiwalled carbon nanotubes – its application in NEMS
- 2005
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Ingår i: AIP COnference Proceedings. - 0094-243X .- 1551-7616. ; 786, s. 620-623
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Tidskriftsartikel (refereegranskat)abstract
- Nanoelectromechanical systems (NEMS) are a rapidly growing area of research. We discuss here the fabrication of two different three terminal nanorelay structures based on multi-walled carbon nanotubes (MWNT). Using a gate voltage the whole MWNT can be deflected and the tip of the carbon nanotube can be moved closer to a drain electrode making physical contact. In another device structure the carbon nanotubes are shorter so they never can get real physical contact with the drain electrode, instead this device is based on the process of electron field emission from the MWNT.
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| 72. |
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| 73. |
- Sveningsson, Martin, 1977, et al.
(författare)
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Quantifying temperature-enhanced electron field emission from individual carbon nanotubes
- 2005
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Ingår i: Physical Review B. - : American Physical Society. ; 72:8
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Tidskriftsartikel (refereegranskat)abstract
- The electron field emission properties of individual multiwalled carbon nanotubes have been examined using a combined STM-TEM microscope. The measured electron emission, for low emission currents, can be fitted with a standard Fowler-Nordheim model. For higher electron emission, above 10 µA for an individual carbon nanotube, we observe a significantly increased emission current leading to a nonlinear Fowler-Nordheim plot. The nonlinearity is caused by thermally enhanced electron emission due to Ohmic heating of the carbon nanotube. This is verified by modeling the electron field emission current. In addition to the influence of radiative cooling and the temperature dependence of the nanotube resistivity, we clearly show that a consideration of the temperature change due to the electron emission process itself, known as the Nottingham effect, is crucial to obtain good agreement with the experimental data.
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| 74. |
- Svensson, Johannes, 1978, et al.
(författare)
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A carbon nanotube gated carbon nanotube transistor with 5 ps gate
- 2008
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Semiconducting carbon nanotubes (CNTs) are attractive as channel material for field-effect transistors due to their high carrier mobility. In this paper we show that a local CNT gate can provide a significant improvement in the subthreshold slope of a CNT transistor compared to back gate switching and provide gate delays as low as 5 ps. The CNT gated CNT transistor devices are fabricated using a two-step chemical vapour deposition technique. The measured transfer characteristics are in very good agreement with theoretical modelling results that provide confirmation of the operating principle of the transistors. Gate delays below 2 ps should be readily achievable by reducing the thickness of the gate dielectric.
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| 75. |
- Svensson, Johannes, 1978, et al.
(författare)
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Carbon Nanotube Diameter Dependence of the Schottky Barrier Height for Pd – Carbon Nanotube Contacts
- 2009
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:17
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Tidskriftsartikel (refereegranskat)abstract
- Direct measurements are presented of the Schottky barrier (SB) heights of carbon nanotube devices contacted with Pd electrodes. The SB barrier heights were determined from the activation energy of the temperature-dependent thermionic emission current in the off-state of the devices. The barrier heights generally decrease with increasing diameter of the nanotubes and they are in agreement with the values expected when assuming little or no influence of Fermi level pinning.
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| 76. |
- Svensson, Johannes, 1978, et al.
(författare)
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Field emission induced deformations in SiO2 during CVD growth of carbon nanotubes
- 2006
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 243, s. 3524-3527
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Tidskriftsartikel (refereegranskat)abstract
- The application of an electric field while growing carbon nanotubes with CVD can induce deformations in the SiO2 substrate. The effect is attributed to field emission from the tubes and Marangoni convection in a small molten SiO2 region underneath the tubes. Postgrowth deformation has been performed as well as large scale deformations using the collective effect of many field emitters. The porosity of one type of deformation is also examined and discussed.
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| 77. |
- Svensson, Johannes, 1978, et al.
(författare)
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Marangoni effect in SiO(2) during field-directed chemical vapor deposition growth of carbon nanotubes
- 2006
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Ingår i: Physical Review B. - 0163-1829. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Intense local heating of SiO2 is shown to occur during chemical vapor deposition growth of single-walled carbon nanotubes in the presence of an electric field. This gives rise to the Marangoni effect where strong convection currents are induced in the molten SiO2 layer. Nanoscale trenches and bumps are formed in the insulating layer directly below the growing nanotube.
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| 78. |
- Tarasov, Mikhail, 1954, et al.
(författare)
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Carbon nanotube based bolometer
- 2006
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Ingår i: JETP Letters. - 0021-3640 .- 1090-6487. ; 84:5, s. 267-270
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Tidskriftsartikel (refereegranskat)abstract
- The contacts of single carbon nanotubes and bundles of carbon nanotubes with superconducting and metallic electrodes are investigated in order to create bolometers and electron coolers. Tunneling contacts of the carbon nanotubes with aluminum electrodes are obtained. The current-voltage characteristics of junctions are analyzed for temperatures from room temperature to 300 mK. The resistance of individual nanotubes is primarily determined by defects and is too large for applications. The use of the bundles of carbon nanotubes makes it possible to considerably reduce the resistance of the bolometer, which is determined by a small number of conducting tubes with good tunneling contacts with the electrodes. The energy gap is equal to hundreds and tens of millivolt in the former and latter cases, respectively. Structures containing bundles of carbon nanotubes can be described in a model with a Schottky barrier. The samples with bundles of carbon nanotubes exhibit the bolometric response to external high-frequency radiation at a frequency of 110 GHz with an amplitude up to 100 μV and a temperature voltage response to 0.4 mV/K.
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| 79. |
- Tarasov, Mikhail, 1954, et al.
(författare)
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Carbon nanotube bolometers
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90
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Tidskriftsartikel (refereegranskat)abstract
- A cryogenic bolometer has been fabricated using a bundle of single-walled carbon nanotubes as absorber. A bolometric response was observed when the device was exposed to radiation at 110 GHz. The temperature response was 0.4 mV/K, with an intrinsic electrical responsivity at low frequency up to 109 V/W and noise equivalent power of 3×10−16 W/Hz1/2 at 4.2 K. The response is largest at input power levels of a few femtowatts and decreases inversely proportional to the input power. Low frequency noise shows a 1/f dependence.
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| 80. |
- Wang, Teng, 1983, et al.
(författare)
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Low temperature transfer and formation of carbon nanotube arrays by imprinted conductive adhesive
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:9
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Tidskriftsartikel (refereegranskat)abstract
- This letter demonstrates the transfer and formation of aligned carbon nanotube (CNT) arrays at low temperature by imprinted conductive adhesive. A thermoplastic isotropic conductive adhesive is patterned by an imprint and heat transfer process. The CNTs grown by thermal chemical vapor deposition are then transferred to another substrate by the conductive adhesive, forming predefined patterns. The current-voltage response of the transferred CNT bundles verifies that good electrical connection has been established. This process can enable the integration of CNTs into various temperature-sensitive processeses and materials.
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