Semiconducting Enriched Carbon Nanotube Aligned Arrays of Tunable Density and Their Electrical Transport Properties

Sarker, Biddut K.; Shekhar, Shashank; Khondaker, Saiful I.

doi:10.1021/nn201314t

Cited by 98 publications

(135 citation statements)

References 55 publications

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“…[1][2][3][4][5][6][7][8] One of the most promising applications of CNTs is in field-emission devices, [9][10][11][12][13][14] which is enabled by their extremely high aspect ratio, tremendous mechanical strength, and remarkable electrical and thermal conductivities. 15,16 Efforts have been made to improve scalable CNT-based field-emission devices, but many structural aspects that play significant roles in such devices have yet to be explored, e.g., a more suitable substrate to support CNT emitters.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Field-Emission Performance from Carbon Nanotube Emitters on Nickel Foam Cathodes

Song

Han

et al. 2016

Journal of Elec Materi

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We present a three-dimensionally configured cathode with enhanced fieldemission performance formed by combining carbon nanotube (CNT) emitters with a nickel foam (NiF) substrate via a conventional screen-printing technique. The CNT/NiF cathode has low turn-on electric field of 0.53 V lm À1 (with current density of 10 lA cm À2 ) and threshold electric field of 0.87 V lm À1 (with current density of 0.1 mA cm À2 ), and a very high field enhancement factor of 1.4 9 10 4 . The porous structure of the NiF substrate can greatly improve the field-emission properties due to its large specific surface area that can accommodate more CNTs and increase the emitter density, as well as its high electrical and thermal conductivities that facilitate current transition and heat dissipation in the cathode. Most importantly, the local electric field was also enhanced by the multistage effect resulting from the rough metal surface, which furthermore leads to a high field enhancement factor. We believe that this improved field-emission performance makes such cathodes promising candidates for use in various field-emission applications.

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Section: Introductionmentioning

confidence: 99%

Enhanced Field-Emission Performance from Carbon Nanotube Emitters on Nickel Foam Cathodes

Song

Han

et al. 2016

Journal of Elec Materi

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“…The fringing-field dielectrophoretic nanotube assembly yields a much higher degree of alignment, with virtually all nanotubes confined within ±6°of one another as shown in Fig. 2a, than those generated by other techniques for solution-processed nanotubes, including the planar dielectrophoresis, Langmuir-Schaefer method and chemical placement, where nanotubes are reported to lie within ± 15°B ± 30°deviating from the major alignment direction 14,16,24 . Such high degree of alignment is also supported by the large, c.a.…”

Section: Resultsmentioning

confidence: 90%

“…Assembled arrays are typically rich of various curving and wiggling defects due to random hydrodynamic force and Brownian motion of nanotubes. More importantly, the formation of commonly observed multilayer defects makes it almost impossible to achieve a meaningful inter-tube pitch of o40 nm or any pitch uniformity control [23][24][25][26] .…”

mentioning

confidence: 99%

Fringing-field dielectrophoretic assembly of ultrahigh-density semiconducting nanotube arrays with a self-limited pitch

2014

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One key challenge of realizing practical high-performance electronic devices based on singlewalled carbon nanotubes is to produce electronically pure nanotube arrays with both a minuscule and uniform inter-tube pitch for sufficient device-packing density and homogeneity. Here we develop a method in which the alternating voltage-fringing electric field formed between surface microelectrodes and the substrate is utilized to assemble semiconducting nanotubes into well-aligned, ultrahigh-density and submonolayered arrays, with a consistent pitch as small as 21±6 nm determined by a self-limiting mechanism, based on the unique field focusing and screening effects of the fringing field. Field-effect transistors based on such nanotube arrays exhibit record high device transconductance (450 mS mm À 1 ) and decent on current per nanotube (B1 mA per tube) together with high on/off ratios at a drain bias of À 1 V.

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“…After the assembly, we opened an window of channel length 2 µm and width 25 µm on the m-CNTs arrays via electron beam lithography (EBL) and etched away the exposed area using oxygen plasma. [30,31] We calculated linear mobility (μ) using the standard formula: [15] We characterized a total of 26 devices (13 m-CNT/s-CNT and 13 Pd/s-CNT) with the same linear density of 1 s-CNT/µm in the channel. The summary of the device performance is shown in the box plots in Figure 4 (also Table S1).…”

Section: Resultsmentioning

confidence: 99%

“…[15] The Pd electrodes deposited on Si/SiO 2 The Characterization of the Devices: The SEM and AFM images of the devices were taken by the Zeiss Ultra-55 SEM and the Dimension 3100 AFM (Veeco). The electronic transport measurements at both room and low temperatures were taken using DL instruments 1211 current preamplifier and Keithley 2400 source meter interfaced with LabView program.…”

Section: The Fabrication Of S-cnt Tfts With Pd Electrodes (Control Dementioning

confidence: 99%

High performance semiconducting enriched carbon nanotube thin film transistors using metallic carbon nanotubes as electrodes

2014

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High-performance solution-processed short-channel carbon nanotube (CNT) thin film transistors (TFTs) are fabricated using densely aligned arrays of metallic CNTs (mCNTs) as source and drain electrodes, and aligned arrays of semiconducting enriched CNTs (s-CNTs) as channel material. The electrical transport measurements at room temperature show that the m-CNT contacted s-CNT array devices with a 2 µm channel length perform superiorly to those of control Pd contacted s-CNT devices. The m-CNT contacted devices exhibit a maximum (average) on-conductance of 36.5 µS (19.2 µS), transconductance of 2.6 µS (1.2 µS), mobility of 51 cm 2 /Vs (25 cm 2 /Vs), and current onoff ratio of 1.1×10 6 (2.5×10 5 ). These values are almost an order of magnitude higher than that of control Pd contacted devices with the same channel length and s-CNT linear density. The low temperature charge transport measurements suggest that these improved performances are due to the lower charge injection barrier of m-CNT/s-CNT array devices compared to Pd/s-CNT array devices. We attribute the lower injection barrier to unique geometry of our devices. In addition to using semiconducting enriched CNT, our results suggest that using metallic CNT as an electrode can significantly enhance the performance of CNT TFTs.

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Semiconducting Enriched Carbon Nanotube Aligned Arrays of Tunable Density and Their Electrical Transport Properties

Cited by 98 publications

References 55 publications

Enhanced Field-Emission Performance from Carbon Nanotube Emitters on Nickel Foam Cathodes

Enhanced Field-Emission Performance from Carbon Nanotube Emitters on Nickel Foam Cathodes

Fringing-field dielectrophoretic assembly of ultrahigh-density semiconducting nanotube arrays with a self-limited pitch

High performance semiconducting enriched carbon nanotube thin film transistors using metallic carbon nanotubes as electrodes

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