101
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Bushmaker AW, Deshpande VV, Hsieh S, Bockrath MW, Cronin SB. Gate voltage controllable non-equilibrium and non-ohmic behavior in suspended carbon nanotubes. NANO LETTERS 2009; 9:2862-2866. [PMID: 19719105 DOI: 10.1021/nl901042w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this work, we measure the electrical conductance and temperature of individual, suspended quasi-metallic single-walled carbon nanotubes under high voltage biases using Raman spectroscopy, while varying the doping conditions with an applied gate voltage. By applying a gate voltage, the high-bias conductance can be switched dramatically between linear (Ohmic) behavior and nonlinear behavior exhibiting negative differential conductance (NDC). Phonon populations are observed to be in thermal equilibrium under Ohmic conditions but switch to nonequilibrium under NDC conditions. A typical Landauer transport model assuming zero bandgap is found to be inadequate to describe the experimental data. A more detailed model is presented, which incorporates the doping dependence in order to fit this data.
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Affiliation(s)
- Adam W Bushmaker
- Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA
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102
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Hobbie EK, Fagan JA, Obrzut J, Hudson SD. Microscale polymer-nanotube composites. ACS APPLIED MATERIALS & INTERFACES 2009; 1:1561-1566. [PMID: 20355961 DOI: 10.1021/am9002205] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Polymer colloids with an interfacial coating of purified single-wall carbon nanotubes (SWCNTs) are synthesized from length- and type-sorted SWCNTs. Aqueous nanotube suspensions sorted through density-gradient ultracentrifugation are used to emulsify spherical polymer colloids of microscale dimensions that are characterized through a combination of optical microscopy, transmission electron microscopy, and impedance spectroscopy. The SWCNT-polymer composite particles exhibit electrical conductivities comparable to or better than those of bulk SWCNT-polymer composites at nanotube loadings of more than 1 order of magnitude lower. The composite particles retain the unique electronic and optical characteristics of the parent SWCNT solution with potential applications as microelectronic and microoptical components.
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Affiliation(s)
- Erik K Hobbie
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
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103
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104
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Wang X, Li X, Zhang L, Yoon Y, Weber PK, Wang H, Guo J, Dai H. N-Doping of Graphene Through Electrothermal Reactions with Ammonia. Science 2009; 324:768-71. [PMID: 19423822 DOI: 10.1126/science.1170335] [Citation(s) in RCA: 884] [Impact Index Per Article: 58.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Xinran Wang
- Department of Chemistry and Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
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105
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Svensson J, Sourab AA, Tarakanov Y, Lee DS, Park SJ, Baek SJ, Park YW, Campbell EEB. The dependence of the Schottky barrier height on carbon nanotube diameter for Pd-carbon nanotube contacts. NANOTECHNOLOGY 2009; 20:175204. [PMID: 19420588 DOI: 10.1088/0957-4484/20/17/175204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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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106
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Aïssa B, El Khakani MA. The channel length effect on the electrical performance of suspended-single-wall-carbon-nanotube-based field effect transistors. NANOTECHNOLOGY 2009; 20:175203. [PMID: 19420587 DOI: 10.1088/0957-4484/20/17/175203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the electrical performance of field effect transistor (FET) nanodevices based on suspended single-wall carbon nanotubes (SWCNTs) grown by our 'all-laser' synthesis process. The attractiveness of the proposed approach lies in the combination of standard microfabrication processing with the in situ 'all-laser' localized growth of SWCNTs, offering an affordable way of directly integrating SWCNTs into nanodevices. The 'all-laser' process uses the same KrF excimer laser (248 nm), first, to deposit the nanocatalyzed electrodes and, in a second step, to grow the SWCNTs in a suspended geometry, achieving thereby the lateral bridging of the electrodes. The nanocatalyzed electrodes consist of a multilayer stack sandwiching a catalyst nanolayer ( approximately 5 nm thick) composed of Co/Ni nanoparticles. The 'all-laser' grown SWCNTs ( approximately 1 nm diameter) are most often seen to self-assemble into bundles (10-20 nm diameter) and to bridge laterally the various gap lengths (in the 2-10 microm investigation range) separating adjacent electrodes. The suspended-SWCNT-based FETs were found to behave as p-type transistors, in air and at room temperature, with very high ON/OFF switching ratios (whose magnitude markedly increases as the active channel length is reduced). For the shortest gap (i.e. 2 microm), the suspended-SWCNT-based FETs exhibited not only an ON/OFF switching ratio in excess of seven orders of magnitude, but also an ON-state conductance as high as 3.26 microS. Their corresponding effective carrier mobility was estimated (at V(SD) = 100 mV) to a value of approximately 4000 cm(2) V(-1) s(-1), which is almost ten times higher than the hole mobility in single-crystal silicon at room temperature.
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Affiliation(s)
- B Aïssa
- Institut National de la Recherche Scientifique, INRS-Energie, Matériaux et Télécommunications, Varennes, QC, Canada
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107
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Kaul AB. Gas sensing with long, diffusively contacted single-walled carbon nanotubes. NANOTECHNOLOGY 2009; 20:155501. [PMID: 19420548 DOI: 10.1088/0957-4484/20/15/155501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A carbon nanotube thermal-conductivity-based pressure or gas sensor is described, which utilizes 5-10 microm long, diffusively contacted single-walled nanotubes (SWNTs). Low temperature electrical transport measurements for these tubes were suggestive of a thermally activated hopping mechanism for electron localization, where a hopping energy of approximately 39 meV was computed. A negative differential conductance regime was also detected in suspended tubes, released using critical point drying, at high bias voltages. The pressure or gas sensitivity increased more dramatically as the bias power was increased up to 14 muW, which was interpreted in the context of the high optical phonon density in the suspended SWNTs. Such devices are promising for use as pressure sensors, as well as for the chemical identification of species having differing gas thermal conductivities.
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Affiliation(s)
- Anupama B Kaul
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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108
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Yu WJ, Kim UJ, Kang BR, Lee IH, Lee EH, Lee YH. Adaptive logic circuits with doping-free ambipolar carbon nanotube transistors. NANO LETTERS 2009; 9:1401-1405. [PMID: 19281215 DOI: 10.1021/nl803066v] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A CMOS-like inverter was integrated by using ambipolar carbon nanotube (CNT) transistors without doping. The ambipolar CNT transistors automatically configure themselves to play a role as an n-type or p-type transistor in a logic circuit depending on the supply voltage (V(DD)) and ground. A NOR (NAND) gate is adaptively converted to a NAND (NOR) gate. This adaptiveness of logic gates exhibiting two logic gate functions in a single logic circuit offers a new opportunity for designing logic circuits with high integration density for next generation applications.
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Affiliation(s)
- Woo Jong Yu
- Department of Energy Science, BK21 Physics Division, Sungkyunkwan Advanced Institute of Nanotechnology, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan University, Suwon, South Korea
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109
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Belloni F, Kütahyali C, Rondinella VV, Carbol P, Wiss T, Mangione A. Can carbon nanotubes play a role in the field of nuclear waste management? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:1250-1255. [PMID: 19350887 DOI: 10.1021/es802764g] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Fabio Belloni
- European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany
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110
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Raj K, Pan X, Zhang Q, Chan-Park MB, Pingqi G. Chemically induced air- stable unipolar-to-ambipolar conversion of carbon nanotube field effect transistors. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.01.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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111
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Xiong W, Zhou YS, Mahjouri-Samani M, Yang WQ, Yi KJ, He XN, Liou SH, Lu YF. Self-aligned growth of single-walled carbon nanotubes using optical near-field effects. NANOTECHNOLOGY 2009; 20:025601. [PMID: 19417270 DOI: 10.1088/0957-4484/20/2/025601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Self-aligned growth of ultra-short single-walled carbon nanotubes (SWNTs) was realized by utilizing optical near-field effects in a laser-assisted chemical vapor deposition (LCVD) process. By introducing the optical near-field effects, bridge structures containing single suspended SWNT channels were successfully fabricated through the LCVD process at a relatively low substrate temperature. Raman spectroscopy and I-V analyses have been carried out to characterize the SWNT-bridge structures. Numerical simulations using a high-frequency structure simulator revealed that significant enhancement of local heating occurs at metallic electrode tips under laser irradiation; it is about one order of magnitude higher than that in the rest of the electrodes. This technique suggests a novel approach to in situ low-temperature fabrication of SWNT-based devices in a precisely controlled manner, based on the nanoscale heating enhancement induced by the optical near-field effects.
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Affiliation(s)
- W Xiong
- Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0511, USA
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112
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Zhang ZH, Qiu M, Deng XQ, Ding KH, Zhang H. Electronic transport of unimolecular devices with a group coadsorbed on one electrode surface: A density functional study. J Chem Phys 2009; 130:184703. [DOI: 10.1063/1.3122384] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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113
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Noel Y, D'arco P, Demichelis R, Zicovich-Wilson CM, Dovesi R. On the use of symmetry in theab initioquantum mechanical simulation of nanotubes and related materials. J Comput Chem 2009; 31:855-62. [DOI: 10.1002/jcc.21370] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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114
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Sgobba V, Guldi DM. Carbon nanotubes—electronic/electrochemical properties and application for nanoelectronics and photonics. Chem Soc Rev 2009; 38:165-84. [DOI: 10.1039/b802652c] [Citation(s) in RCA: 448] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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115
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Wei D, Zhang Y, Yang Y, Hasko DG, Chu D, Teo KBK, Amaratunga GAJ, Milne WI. Transformation of unipolar single-walled carbon nanotube field effect transistors to ambipolar induced by polystyrene nanosphere assembly. ACS NANO 2008; 2:2526-2530. [PMID: 19206288 DOI: 10.1021/nn800706v] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have fabricated single-walled carbon nanotube (SWNT) field effect transistors (FETs) with molybdenum source and drain contacts. Normally, these devices operate only as p-channel transistors, however, after polystyrene latex nanospheres were attached to the nanotubes close to the contacts, they changed to ambipolar operation. This strategy provides a simple method to modify the electrical behavior of unipolar SWNT-FETs by influencing the gate-channel electric field distribution and offset charge, so enabling complementary circuits to be fabricated.
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Affiliation(s)
- Di Wei
- Electrical Engineering Division, Engineering Department, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, U.K
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116
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Kim KH, Kim JH, Huang XJ, Yoo SM, Lee SY, Choi YK. Doping-free nanoscale complementary carbon-nanotube field-effect transistors with DNA-templated molecular lithography. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:1959-1963. [PMID: 18924128 DOI: 10.1002/smll.200800226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Kuk-Hwan Kim
- School of Electrical Engineering and Computer Science, KAIST, Daejeon, Republic of Korea
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117
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Anghel C, Derycke V, Filoramo A, Lenfant S, Giffard B, Vuillaume D, Bourgoin JP. Nanotube transistors as direct probes of the trap dynamics at dielectric-organic interfaces of interest in organic electronics and solar cells. NANO LETTERS 2008; 8:3619-3625. [PMID: 18947213 DOI: 10.1021/nl801543k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The high sensitivity of nanotube transistors is used for the first time as a probe to study charge dynamics at a dielectric/polymer (polythiophene) interface, an inorganic/organic junction of particular importance for organic solar cells, and organic field effect transistors (OFETs). A carbon nanotube field effect transistor is coated with a thin film of a photoconductive polymer and photoexcited so as to generate carriers in the structure. Comparison between devices using SiO2 and TiO2 as gate dielectric reveals the critical role of the dielectric and clearly elucidates the relative contributions of the polymer and the dielectric layers on the separation, trapping, and relaxation of photogenerated charges.
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Affiliation(s)
- Costin Anghel
- Laboratoire d'Electronique Moleculaire, Service de Physique de L'Etat Condense (CNRS URA 2464), CEA, IRAMIS, F-91191 Gif-sur-Yvette, France
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118
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Xia F, Steiner M, Lin YM, Avouris P. A microcavity-controlled, current-driven, on-chip nanotube emitter at infrared wavelengths. NATURE NANOTECHNOLOGY 2008; 3:609-613. [PMID: 18839000 DOI: 10.1038/nnano.2008.241] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 07/24/2008] [Indexed: 05/26/2023]
Abstract
Recent studies of the optical properties of semiconducting single-walled carbon nanotubes suggest that these truly nanometre-scale systems have a promising future in nanophotonics, in addition to their well-known potential in electronics. Semiconducting single-walled nanotubes have a direct, diameter-dependent bandgap and can be excited readily by current injection, which makes them attractive as nano-emitters. The electroluminescence is spectrally broad, spatially non-directional, and the radiative yield is low. Here we report the monolithic integration of a single, electrically excited, semiconducting nanotube transistor with a planar lambda/2 microcavity, thus taking an important first step in the development of nanotube-based nanophotonic devices. The spectral full-width at half-maximum of the emission is reduced from approximately 300 to approximately 40 nm at a cavity resonance of 1.75 microm, and the emission becomes highly directional. The maximum enhancement of the radiative rate is estimated to be 4. We also show that both the optically and electrically excited luminescence of single-walled nanotubes involve the same E11 excitonic transition.
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Affiliation(s)
- Fengnian Xia
- Department of Nanometer Scale Science and Technology, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA.
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119
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Kim KK, Bae JJ, Park HK, Kim SM, Geng HZ, Park KA, Shin HJ, Yoon SM, Benayad A, Choi JY, Lee YH. Fermi Level Engineering of Single-Walled Carbon Nanotubes by AuCl3 Doping. J Am Chem Soc 2008; 130:12757-61. [DOI: 10.1021/ja8038689] [Citation(s) in RCA: 217] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ki Kang Kim
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Jung Jun Bae
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Hyeon Ki Park
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Soo Min Kim
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Hong-Zhang Geng
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Kyung Ah Park
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Hyeon-Jin Shin
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Seon-Mi Yoon
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Anass Benayad
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Jae-Young Choi
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
| | - Young Hee Lee
- BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea
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120
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Adam E, Aguirre CM, Marty L, St-Antoine BC, Meunier F, Desjardins P, Ménard D, Martel R. Electroluminescence from single-wall carbon nanotube network transistors. NANO LETTERS 2008; 8:2351-5. [PMID: 18598091 DOI: 10.1021/nl8011825] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The electroluminescence (EL) properties from single-wall carbon nanotube network field-effect transistors (NNFETs) and small bundle carbon nanotube field effect transistors (CNFETs) are studied using spectroscopy and imaging in the near-infrared (NIR). At room temperature, NNFETs produce broad (approximately 180 meV) and structured NIR spectra, while they are narrower (approximately 80 meV) for CNFETs. EL emission from NNFETs is located in the vicinity of the minority carrier injecting contact (drain) and the spectrum of the emission is red shifted with respect to the corresponding absorption spectrum. A phenomenological model based on a Fermi-Dirac distribution of carriers in the nanotube network reproduces the spectral features observed. This work supports bipolar (electron-hole) current recombination as the main mechanism of emission and highlights the drastic influence of carrier distribution on the optoelectronic properties of carbon nanotube films.
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Affiliation(s)
- E Adam
- Regroupement Québécois sur les Matériaux de Pointe (RQMP), Département de Génie Physique, Ecole Polytechnique de Montréal, Montréal, Canada
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121
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Shiau SH, Liu CW, Gau C, Dai BT. Growth of a single-wall carbon nanotube film and its patterning as an n-type field effect transistor device using an integrated circuit compatible process. NANOTECHNOLOGY 2008; 19:105303. [PMID: 21817696 DOI: 10.1088/0957-4484/19/10/105303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This study presents the synthesis of a dense single-wall carbon nanotube (SWNT) network on a silicon substrate using alcohol as the source gas. The nanosize catalysts required are made by the reduction of metal compounds in ethanol. The key point in spreading the nanoparticles on the substrate, so that the SWNT network can be grown over the entire wafer, is making the substrate surface hydrophilic. This SWNT network is so dense that it can be treated like a thin film. Methods of patterning this SWNT film with integrated circuit compatible processes are presented and discussed for the first time in the literature. Finally, fabrication and characteristic measurements of a field effect transistor (FET) using this SWNT film are also demonstrated. This FET is shown to have better electronic properties than any other kind of thin film transistor. This thin film with good electronic properties can be readily applied in the processing of many other SWNT electronic devices.
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Affiliation(s)
- S H Shiau
- Institute of Aeronautics and Astronautics, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan
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122
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Zhang WJ, Zhang JY, Li PJ, Shen X, Zhang QF, Wu JL. The effects of contacts and ambipolar electrical transport in nitrogen doped multiwall carbon nanotubes. NANOTECHNOLOGY 2008; 19:085202. [PMID: 21730720 DOI: 10.1088/0957-4484/19/8/085202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The electrical transport properties of pristine single wall carbon nanotubes (SWCNTs) and lower nitrogen content doped multiwall carbon nanotubes (MWCNTs) (lower than in the experiments of Xiao et al (2005 J. Am. Chem. Soc. 127 8614)) in contact with Au and Pt were studied. Compared with pristine SWCNTs, the Fermi level of the lower nitrogen content doped MWCNTs also moved to the valence band edge with the contact metal's work function increasing. In contrast to Derycke et al' s results (2002 Appl. Phys. Lett. 80 2773), the lower nitrogen content doped MWCNTs exhibited ambipolar behavior, and increasing the doping level led to a reduction of the Schottky barrier height of electrons. Consistent with theoretical calculations, the results support the opinion that the degree of Fermi level pinning is minor for doped carbon nanotubes.
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Affiliation(s)
- W J Zhang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, People's Republic of China
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124
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Lee EJH, Balasubramanian K, Dorfmüller J, Vogelgesang R, Fu N, Mews A, Burghard M, Kern K. Electronic-band-structure mapping of nanotube transistors by scanning photocurrent microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:2038-2042. [PMID: 18030672 DOI: 10.1002/smll.200700418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Eduardo J H Lee
- Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
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125
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Gómez-Navarro C, Weitz RT, Bittner AM, Scolari M, Mews A, Burghard M, Kern K. Electronic transport properties of individual chemically reduced graphene oxide sheets. NANO LETTERS 2007; 7:3499-503. [PMID: 17944526 DOI: 10.1021/nl072090c] [Citation(s) in RCA: 983] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Individual graphene oxide sheets subjected to chemical reduction were electrically characterized as a function of temperature and external electric fields. The fully reduced monolayers exhibited conductivities ranging between 0.05 and 2 S/cm and field effect mobilities of 2-200 cm2/Vs at room temperature. Temperature-dependent electrical measurements and Raman spectroscopic investigations suggest that charge transport occurs via variable range hopping between intact graphene islands with sizes on the order of several nanometers. Furthermore, the comparative study of multilayered sheets revealed that the conductivity of the undermost layer is reduced by a factor of more than 2 as a consequence of the interaction with the Si/SiO2 substrate.
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Affiliation(s)
- Cristina Gómez-Navarro
- Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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126
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Abstract
The semiconductor industry has been able to improve the performance of electronic systems for more than four decades by making ever-smaller devices. However, this approach will soon encounter both scientific and technical limits, which is why the industry is exploring a number of alternative device technologies. Here we review the progress that has been made with carbon nanotubes and, more recently, graphene layers and nanoribbons. Field-effect transistors based on semiconductor nanotubes and graphene nanoribbons have already been demonstrated, and metallic nanotubes could be used as high-performance interconnects. Moreover, owing to the excellent optical properties of nanotubes it could be possible to make both electronic and optoelectronic devices from the same material.
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Affiliation(s)
- Phaedon Avouris
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
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127
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Wang CW, Pan CY, Wu HC, Shih PY, Tsai CC, Liao KT, Lu LL, Hsieh WH, Chen CD, Chen YT. In situ detection of chromogranin a released from living neurons with a single-walled carbon-nanotube field-effect transistor. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:1350-5. [PMID: 17576645 DOI: 10.1002/smll.200600723] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Affiliation(s)
- Chen-Wei Wang
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
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128
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Freitag M, Tsang JC, Bol A, Yuan D, Liu J, Avouris P. Imaging of the Schottky barriers and charge depletion in carbon nanotube transistors. NANO LETTERS 2007; 7:2037-42. [PMID: 17559288 DOI: 10.1021/nl070900e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The photovoltage produced by local illumination at the Schottky contacts of carbon nanotube field-effect transistors varies substantially with gate voltage. This is particularly pronounced in ambipolar nanotube transistors where the photovoltage switches sign as the device changes from p-type to n-type. The detailed transition through the insulating state can be recorded by mapping the open-circuit photovoltage as a function of excitation position. These photovoltage images show that the band-bending length can grow to many microns when the device is depleted. In our palladium-contacted devices, the Schottky barrier for electrons is much higher than that for holes, explaining the higher p-type current in the transistor. The depletion width is 1.5 mum near the n-type threshold and smaller than our resolution of 400 nm near the p-type threshold. Internal photoemission from the metal contact to the carbon nanotube and thermally assisted tunneling through the Schottky barrier are observed in addition to the photocurrent that is generated inside the carbon nanotube.
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Affiliation(s)
- Marcus Freitag
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
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129
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Hall AR, Falvo MR, Superfine R, Washburn S. Electromechanical response of single-walled carbon nanotubes to torsional strain in a self-contained device. NATURE NANOTECHNOLOGY 2007; 2:413-416. [PMID: 18654324 DOI: 10.1038/nnano.2007.179] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 05/18/2007] [Indexed: 05/26/2023]
Abstract
Nanoscale electronics seeks to decrease the critical dimension of devices in order to improve performance while reducing power consumption. Single-walled carbon nanotubes fit well with this strategy because, in addition to their molecular size, they demonstrate a number of unique electronic, mechanical and electromechanical properties. In particular, theory predicts that strain can have a large effect on the band structure of a nanotube, which, in turn, has an influence on its electron transport properties. This has been demonstrated in experiments where axial strain was applied by a scanning probe. Theory also predicts that torsional strain can influence transport properties, which was observed recently in multiwalled nanotubes. Here we present the first experimental evidence of an electromechanical effect from torsional strain in single-walled nanotubes, and also the first measurements of piezoresistive response in a self-contained nanotube-based nanoelectromechanical structure.
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Affiliation(s)
- Adam R Hall
- Curriculum in Applied and Materials Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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130
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Abstract
Low-frequency "1/f" noise is a major issue for nanoscale devices such at carbon nanotube transistors. We show that nanoscale ballistic transistors give voltage-dependent sensitivity to the intrinsic potential fluctuations from nearby charge traps. A distinctive dependence on gate voltage is predicted, without reference to the number of carriers. This dependence is confirmed by comparison with recent measurements of nanotube transistors. Possible ways of decreasing the noise are discussed.
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Affiliation(s)
- J Tersoff
- IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
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131
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Kim DH, Huang J, Shin HK, Roy S, Choi W. Transport phenomena and conduction mechanism of single-walled carbon nanotubes (SWNTs) at Y- and crossed-junctions. NANO LETTERS 2006; 6:2821-5. [PMID: 17163712 DOI: 10.1021/nl061977q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This letter illustrates the transport phenomena associated with single-walled carbon nanotube (SWNT) junctions of Y- and cross-configurations. Localized gating effect exhibited by Y- and crossed-junctions suggests the resemblance of their electrical characteristics with ambipolar and unipolar p-type FETs, respectively. Temperature dependence of the I-V characteristics reveals that the conduction mechanism in the said SWNT junctions is governed by thermionic emission at temperatures above 100 K and by tunneling at T < 100 K. In-depth analysis of current transport through the crossed- and Y-junction SWNTs is significant in view of their predominant influence on the electrical performance of carbon nanotube networks (CNT-mat).
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Affiliation(s)
- Do-Hyun Kim
- Department of Mechanical and Materials Engineering, Florida International University, Miami, Florida 33174, USA
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132
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Klinke C, Afzali A, Avouris P. Interaction of solid organic acids with carbon nanotube field effect transistors. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.08.090] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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133
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Chen YF, Fuhrer MS. Tuning from thermionic emission to ohmic tunnel contacts via doping in Schottky-barrier nanotube transistors. NANO LETTERS 2006; 6:2158-62. [PMID: 16968044 DOI: 10.1021/nl061379b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Electrical power >1 mW is dissipated in semiconducting single-walled carbon nanotube devices in a vacuum. After high-power treatment, devices exhibit lower on currents and intrinsic, ambipolar behavior with near-ideal thermionic emission from Schottky barriers of height one-half the band gap. Upon exposure to air, devices recover p-type behavior, with positive threshold and ohmic contacts. The air-exposed state cannot be explained by a change in contact work function but instead is due to doping of the nanotube.
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Affiliation(s)
- Yung-Fu Chen
- Department of Physics and Center for Superconductivity Research, University of Maryland, College Park, Maryland 20742-4111, USA
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134
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LI HONG, ZHANG QING, LI JINGQI. CHARGE STORAGE IN CARBON NANOTUBE FIELD-EFFECT TRANSISTORS. INTERNATIONAL JOURNAL OF NANOSCIENCE 2006. [DOI: 10.1142/s0219581x06004784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Very significant hysteresis characteristics are found in single wall carbon nanotubes field-effect transistors (CNTFET) fabricated using AC dielectrophoresis method. The CNTFETs show ambipolar characteristics. Two clear hysteresis loops are observed when the gate voltage is forward and backward swept. The hysteresis characteristics are studied from room temperature down to 16 K. It is found that the hysteresis loops become smaller as temperature is decreased. We suggested that the hysteresis is caused by charge trapping in foreign species covering the single wall carbon nanotube. It is more difficult for charges to transfer into and out of the trapping center at a lower temperature; as a result, the hysteresis loops become much smaller at low temperature.
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Affiliation(s)
- HONG LI
- Microelectronics Center, School of Electrical and Electronics Engineering, Nanyang Technological University, S1-B2c-20, Singapore 639798, Singapore
| | - QING ZHANG
- Microelectronics Center, School of Electrical and Electronics Engineering, Nanyang Technological University, S1-B2c-20, Singapore 639798, Singapore
| | - JINGQI LI
- Microelectronics Center, School of Electrical and Electronics Engineering, Nanyang Technological University, S1-B2c-20, Singapore 639798, Singapore
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135
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LI JINGQI, ZHANG QING, CHAN-PARK MARYB, YAN YEHAI. ANNEALING EFFECTS ON ELECTRIC CONTACTS BETWEEN CARBON NANOTUBES AND ELECTRODES. INTERNATIONAL JOURNAL OF NANOSCIENCE 2006. [DOI: 10.1142/s0219581x06004541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Single wall carbon nanotubes suspended in isopropyl alcohol are placed between two Au electrodes by ac dielectrophoresis method. Total resistance including the contact resistance and intrinsic tube resistance is found to decrease from 105–106 Ω for as-prepared samples to 104 Ω after annealing at 300°C in ambient environment. Measured I–V curves and Schottky barrier heights suggest that the electric contacts are changed from Schottky to Ohmic characteristics after annealing. These results demonstrate that annealing in ambient environment is a simple and efficient way to decrease the contact resistance.
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Affiliation(s)
- JINGQI LI
- Microeletronics Center, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - QING ZHANG
- Microeletronics Center, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - MARY B. CHAN-PARK
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - YEHAI YAN
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 639798, Singapore
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136
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Urita K, Seki S, Utsumi S, Noguchi D, Kanoh H, Tanaka H, Hattori Y, Ochiai Y, Aoki N, Yudasaka M, Iijima S, Kaneko K. Effects of gas adsorption on the electrical conductivity of single-wall carbon nanohorns. NANO LETTERS 2006; 6:1325-8. [PMID: 16834404 DOI: 10.1021/nl060120q] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present significant electrical conductivity responses of the pelletized as-prepared and oxidized (ox-) single-wall carbon nanohorns (SWNHs) on adsorption of CO(2) and O(2). The morphological and pore structures of both pelletized SWNHs were examined by transmission electron microscopy (TEM) and nitrogen adsorption isotherm, leading to explicit evidences of the formation of nanoscale windows on the wall by oxidation. The SWNH and ox-SWNH induced a semiconducting behavior, strongly responded to CO(2) and O(2) adsorptions, and each exhibited n-type- and p-type-like conductivities. The electrical conductivity increase and decrease for CO(2) and O(2) adsorption, respectively, were observed for SWNH, whereas ox-SWNH showed a marked electrical conductivity drop on CO(2) adsorption and almost no change on O(2) adsorption. The dramatically different electrical conductivity response of ox-SWNH is presumed to be ascribed to the annihilation of pentagons in the single graphene wall by oxidation.
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Affiliation(s)
- Koki Urita
- Graduate School of Science and Technology, Chiba University, Japan
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137
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Zhu W, Kaxiras E. The nature of contact between Pd leads and semiconducting carbon nanotubes. NANO LETTERS 2006; 6:1415-9. [PMID: 16834421 DOI: 10.1021/nl0604311] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The contact between semiconducting single-wall carbon nanotubes (SWCNTs) and metallic leads is of central importance to potential electronic device applications. We investigate the nature of the contact of SWCNTs with Pd leads in a fully covered geometry that closely resembles experimental setups. We employ first-principles calculations within density functional theory to obtain the equilibrium structure for representative semiconducting SWCNTs embedded in Pd and analyze their electronic structure features, charge-transfer effects, electrostatic potentials, and Fermi level alignment at the interfaces with the metal contact. We find that there is no electrostatic or Schottky-type barrier to electron transfer between the metal and the nanotube.
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Affiliation(s)
- Wenguang Zhu
- Department of Physics and Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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138
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Guo A, Fu Y, Guan L, Liu J, Shi Z, Gu Z, Huang R, Zhang X. Thermally assisted tunnelling in ambipolar field-effect transistors based on fullerene peapod bundles. NANOTECHNOLOGY 2006; 17:2655-2660. [PMID: 21727520 DOI: 10.1088/0957-4484/17/10/035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the first detailed studies of the electrical transport behaviour of C(70) fullerene peapod bundles at various temperatures from 400 K down to 4 K. With electrical breakdown, we have prepared ambipolar (i.e. both p- and n-type) field-effect transistors (FETs) using fullerene peapod bundles with high levels of performance. This paper focuses on the role of the Schottky barrier and the thermal activation energy in the transport behaviour of fullerene bundles. The temperature dependence of our measurements reveals that transport is dominated by thermally assisted tunnelling in fullerene bundles at low temperature.
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Affiliation(s)
- Ao Guo
- Department of Microelectronics, Peking University, Beijing 100871, People's Republic of China. Key Laboratory for the Physics and Chemistry of Nanodevices, Peking University, Beijing 100871, People's Republic of China
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139
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Klinke C, Hannon JB, Afzali A, Avouris P. Field-effect transistors assembled from functionalized carbon nanotubes. NANO LETTERS 2006; 6:906-10. [PMID: 16683823 DOI: 10.1021/nl052473f] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We have fabricated field-effect transistors from carbon nanotubes using a novel selective placement scheme. We use carbon nanotubes that are covalently bound to molecules containing a hydroxamic acid functionality. The functionalized nanotubes bind strongly to basic metal oxide surfaces, but not to silicon dioxide. Upon annealing, the functionalization is removed, restoring the electronic properties of the nanotubes. The devices thus fabricated show excellent electrical characteristics.
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Affiliation(s)
- Christian Klinke
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA
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140
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Xiang J, Lu W, Hu Y, Wu Y, Yan H, Lieber CM. Ge/Si nanowire heterostructures as high-performance field-effect transistors. Nature 2006; 441:489-93. [PMID: 16724062 DOI: 10.1038/nature04796] [Citation(s) in RCA: 520] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 04/10/2006] [Indexed: 11/08/2022]
Abstract
Semiconducting carbon nanotubes and nanowires are potential alternatives to planar metal-oxide-semiconductor field-effect transistors (MOSFETs) owing, for example, to their unique electronic structure and reduced carrier scattering caused by one-dimensional quantum confinement effects. Studies have demonstrated long carrier mean free paths at room temperature in both carbon nanotubes and Ge/Si core/shell nanowires. In the case of carbon nanotube FETs, devices have been fabricated that work close to the ballistic limit. Applications of high-performance carbon nanotube FETs have been hindered, however, by difficulties in producing uniform semiconducting nanotubes, a factor not limiting nanowires, which have been prepared with reproducible electronic properties in high yield as required for large-scale integrated systems. Yet whether nanowire field-effect transistors (NWFETs) can indeed outperform their planar counterparts is still unclear. Here we report studies on Ge/Si core/shell nanowire heterostructures configured as FETs using high-kappa dielectrics in a top-gate geometry. The clean one-dimensional hole-gas in the Ge/Si nanowire heterostructures and enhanced gate coupling with high-kappa dielectrics give high-performance FETs values of the scaled transconductance (3.3 mS microm(-1)) and on-current (2.1 mA microm(-1)) that are three to four times greater than state-of-the-art MOSFETs and are the highest obtained on NWFETs. Furthermore, comparison of the intrinsic switching delay, tau = CV/I, which represents a key metric for device applications, shows that the performance of Ge/Si NWFETs is comparable to similar length carbon nanotube FETs and substantially exceeds the length-dependent scaling of planar silicon MOSFETs.
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Affiliation(s)
- Jie Xiang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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141
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Marty L, Adam E, Albert L, Doyon R, Ménard D, Martel R. Exciton formation and annihilation during 1D impact excitation of carbon nanotubes. PHYSICAL REVIEW LETTERS 2006; 96:136803. [PMID: 16712017 DOI: 10.1103/physrevlett.96.136803] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Indexed: 05/09/2023]
Abstract
Near-infrared electroluminescence was recorded from unipolar single-wall carbon nanotube field-effect transistors at high drain-source voltages. High resolution spectra reveal resonant light emission originating from the radiative relaxation of excitons rather than heat dissipation. The electroluminescence is induced by only one carrier type and ascribed to 1D impact excitation. An emission quenching is also observed at high field and attributed to an exciton-exciton annihilation process and free carrier generation. The excitons' binding energy in the order of 270 meV for 1.4 nm SWNTs is inferred from the spectral features.
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Affiliation(s)
- L Marty
- Département de Chimie et Regroupement Québécois sur les Matériaux de Pointe, Université de Montréal, Montréal QC H3T1J4, Canada
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142
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Matsuoka K, Kataura H, Shiraishi M. Ambipolar single electron transistors using side-contacted single-walled carbon nanotubes. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2005.10.071] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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143
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Fang WC, Sun CL, Huang JH, Chen LC, Chyan O, Chen KH, Papakonstantinou P. Enhanced Electrochemical Properties of Arrayed CN[sub x] Nanotubes Directly Grown on Ti-Buffered Silicon Substrates. ACTA ACUST UNITED AC 2006. [DOI: 10.1149/1.2166507] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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144
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Son YW, Ihm J, Cohen ML, Louie SG, Choi HJ. Electrical switching in metallic carbon nanotubes. PHYSICAL REVIEW LETTERS 2005; 95:216602. [PMID: 16384166 DOI: 10.1103/physrevlett.95.216602] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Indexed: 05/05/2023]
Abstract
We present first-principles calculations of quantum transport which show that the resistance of metallic carbon nanotubes can be changed dramatically with homogeneous transverse electric fields if the nanotubes have impurities or defects. The change of the resistance is predicted to range over more than 2 orders of magnitude with experimentally attainable electric fields. This novel property has its origin that backscattering of conduction electrons by impurities or defects in the nanotubes is strongly dependent on the strength and/or direction of the applied electric fields. We expect this property to open a path to new device applications of metallic carbon nanotubes.
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Affiliation(s)
- Young-Woo Son
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
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145
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Minoux E, Groening O, Teo KBK, Dalal SH, Gangloff L, Schnell JP, Hudanski L, Bu IYY, Vincent P, Legagneux P, Amaratunga GAJ, Milne WI. Achieving high-current carbon nanotube emitters. NANO LETTERS 2005; 5:2135-8. [PMID: 16277440 DOI: 10.1021/nl051397d] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
When a carbon nanotube emitter is operated at high currents (typically above 1 microA per emitter), a small voltage drop ( approximately few volts) along its length or at its contact generates a reverse/canceling electric field that causes a saturation-like deviation from the classical Fowler-Nordheim behavior with respect to the applied electric field. We present a correction to the Fowler-Nordheim equation to account for this effect, which is experimentally verified using field emission and contact electrical measurements on individual carbon nanotube emitters. By using rapid thermal annealing to improve both the crystallinity of the carbon nanotubes and their electrical contact to the substrate, it is possible to reduce this voltage drop, allowing very high currents of up to 100 microA to be achieved per emitter with no significant deviation from the classical Fowler-Nordheim behavior.
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Affiliation(s)
- Eric Minoux
- Thales Research & Technology, Route départementale 128, 91 767 Palaiseau Cedex, France.
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146
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Hong BH, Small JP, Purewal MS, Mullokandov A, Sfeir MY, Wang F, Lee JY, Heinz TF, Brus LE, Kim P, Kim KS. Extracting subnanometer single shells from ultralong multiwalled carbon nanotubes. Proc Natl Acad Sci U S A 2005; 102:14155-8. [PMID: 16186505 PMCID: PMC1242308 DOI: 10.1073/pnas.0505219102] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report a simple but powerful method for engineering multi-walled carbon nanotubes (MWNTs) by using manipulation by an atomic-force microscope. The successive shell-by-shell extraction process of ultralong MWNTs allows the exposure of the innermost single-walled carbon nanotubes (SWNTs), which have diameters as small as approximately 0.4 nm. The inner-shell extraction process changes the electrical characteristics of the MWNTs. Whereas the outer hollowed-out nanotubes show either metallic or semiconducting character, the innermost SWNTs of small diameter exhibit predominantly metallic transport properties.
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Affiliation(s)
- Byung Hee Hong
- Nanoscale Science and Engineering Center, Columbia University, New York, NY 10027, USA
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147
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Abstract
The known range of chemisorption bonds forms the toolbox for the design of electrical contacts in molecular electronics devices. Double-bond contacts to technologically relevant materials would be attractive for a number of reasons. They are truly single-site, bonding to a single surface atom. They obviate the need for a thiol linkage, and they may be amenable to further modification through olefin-metathesis methodologies. We report olefin-metathesis methods for establishing, varying, and growing thermally stable double-bond contacts to molybdenum carbide, a conducting material.
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Affiliation(s)
- Mohamed Siaj
- Département de chimie, Université Laval, Québec, PQ, Canada G1K 7P4
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148
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Chen Z, Appenzeller J, Knoch J, Lin YM, Avouris P. The role of metal-nanotube contact in the performance of carbon nanotube field-effect transistors. NANO LETTERS 2005; 5:1497-502. [PMID: 16178264 DOI: 10.1021/nl0508624] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Single-wall carbon nanotube field-effect transistors (CNFETs) have been shown to behave as Schottky barrier (SB) devices. It is not clear, however, what factors control the SB size. Here we present the first statistical analysis of this issue. We show that a large data set of more than 100 devices can be consistently accounted by a model that relates the on-current of a CNFET to a tunneling barrier whose height is determined by the nanotube diameter and the nature of the source/drain metal contacts. Our study permits identification of the desired combination of tube diameter and type of metal that provides the optimum performance of a CNFET.
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Affiliation(s)
- Zhihong Chen
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
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149
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Dong L, Chirayos V, Bush J, Jiao J, Dubin VM, Chebian RV, Ono Y, Conley JF, Ulrich BD. Floating-Potential Dielectrophoresis-Controlled Fabrication of Single-Carbon-Nanotube Transistors and Their Electrical Properties. J Phys Chem B 2005; 109:13148-53. [PMID: 16852637 DOI: 10.1021/jp051803h] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a floating-potential dielectrophoresis method used for the first time to achieve controlled alignment of an individual semiconducting or metallic single-walled carbon nanotube (SWCNT) between two electrical contacts with high repeatability. This result is significantly different from previous reports, in which bundles of SWCNTs were aligned between electrode arrays by a conventional dielectrophoresis process where the results were only collected from the control electrode regions. In this study, our alignment focus is not only on the regions of the control electrodes but also on those of the floating electrodes. Our results indicate that bundles of carbon nanotubes along with impurities were first moved into the region between two control electrodes while individual nanotubes without impurities were straightened and aligned between two floating electrodes. The measurements for the back-gated nanotube transistors made by this method displayed an on-off ratio and transconductance of 10(5) and 0.3 microS, respectively. These output and transport properties are comparable with those of nanotube transistors made by other methods. Most importantly, the findings in this study show an effective way to separate individual nanotubes from bundles and impurities and advance the processes for site-selective fabrication of single-SWCNT transistors and related electrical devices.
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Affiliation(s)
- Lifeng Dong
- Department of Physics, Portland State University, Portland, Oregon 97207-0751, USA
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150
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Xiao K, Liu Y, Hu P, Yu G, Sun Y, Zhu D. n-Type Field-Effect Transistors Made of an Individual Nitrogen-Doped Multiwalled Carbon Nanotube. J Am Chem Soc 2005; 127:8614-7. [PMID: 15954765 DOI: 10.1021/ja042554y] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on the fabrication and characterization of field-effect transistor based on an individual multiwalled nitrogen-doped carbon nanotube. Our measurements show that the N-doped carbon nanotubes have n-type properties. The contact properties of the tube and Pt electrodes are also studied in detail. Temperature dependence of two-terminal transport experiments suggests that transport is dominated by thermionic emission and tunneling through a 0.2 eV Schottky contact barrier.
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Affiliation(s)
- Kai Xiao
- Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
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