Separation of Metallic from Semiconducting Single‐Walled Carbon Nanotubes.

Krupke, Ralph; Hennrich, Frank; Loehneysen, H. v.; Kappes, Manfred M.

doi:10.1002/chin.200343198

Cited by 135 publications

(202 citation statements)

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“…19,31 Although the presence of a small percentage of metallic tubes is evident based on three terminal measurements, the high-current response mainly results from multiple ͑parallel͒ channels in the device. 32 The output ͑I ds vs V ds ͒ and the transfer ͑I ds vs V g ͒ characteristics of a typical, purely sc device ͑gap 60͒ are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Parallel arrays of individually addressable single-walled carbon nanotube field-effect transistors

Lastella

Mallick

Woo

et al. 2006

Journal of Applied Physics

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High-throughput field-effect transistors ͑FETs͒ containing over 300 disentangled, high-purity chemical-vapor-deposition-grown single-walled carbon nanotube ͑SWNT͒ channels have been fabricated in a three-step process that creates more than 160 individually addressable devices on a single silicon chip. This scheme gives a 96% device yield with output currents averaging 5.4 mA and reaching up to 17 mA at a 300 mV bias. Entirely semiconducting FETs are easily realized by a high current selective destruction of metallic tubes. The excellent dispersity and nearly-defect-free quality of the SWNT channels make these devices also useful for nanoscale chemical and biological sensor applications.

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Section: Resultsmentioning

confidence: 99%

Parallel arrays of individually addressable single-walled carbon nanotube field-effect transistors

Lastella

Mallick

Woo

et al. 2006

Journal of Applied Physics

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“…For this reason, separation of m-from s-SWNTs has become a fl ourishing subfi eld and in fact enrichment of m/s-SWNTs has been achieved by various techniques including (AC) dielectrophoresis [1], density gradient centrifugation [2], and (DC) agarose gel electrophoresis [3]. A recent review article on separation methods in general, including separation of m-from s-SWNTs, gives a good overview of efforts to date [4].…”

Section: Introductionmentioning

confidence: 99%

Selective suspension in aqueous sodium dodecyl sulfate according to electronic structure type allows simple separation of metallic from semiconducting single-walled carbon nanotubes

Moshammer¹,

Hennrich²,

2009

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Both density gradient centrifugation and gel electrophoresis have been reported to allow high throughput separation of metallic from semiconducting single-walled carbon nanotubes (SWNTs) when using aqueous sodium dodecyl sulphate (SDS) suspensions. We show here that both methods rely on an initial dispersionby-sonication step, which is already selective with respect to electronic structure type. The corresponding aqueous SDS "starting" suspensions obtained after sonication and purifi cation by simple centrifugation (70,000 g, 1 h) contain semiconducting SWNTs primarily in the form of small bundles whereas metallic SWNTs are predominantly suspended as individual tubes. Density gradient centrifugation then separates the bundles from the individual tubes on the basis of differences in their overall buoyant densities. Gel electrophoresis separates the longer bundles from the shorter individual tubes on the basis of their different mobilities. We also demonstrate that such starting suspensions can be fractionated according to electronic structure type by even simpler techniques such as size exclusion chromatography or gel fi ltration, thus opening the way for simple scale-up.

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“…[1][2][3][4] To realize this potential, it is necessary to achieve preferential growth of semiconducting versus metallic nanotubes or enable high degrees of separation [5][6][7][8] of the two types of nanotubes. Here, we present synthesis of high quality SWNTs by a plasma enhanced CVD method at 600°C…”

mentioning

confidence: 99%

Preferential Growth of Semiconducting Single-Walled Carbon Nanotubes by a Plasma Enhanced CVD Method

et al. 2004

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Single-walled carbon nanotubes (SWNT) are grown by a plasma enhanced chemical vapor deposition (PECVD) method at 600°C. The nanotubes are of high quality as characterized by microscopy, Raman spectroscopy, and electrical transport measurements. High performance field effect transistors are obtained with the PECVD nanotubes. Interestingly, electrical characterization reveals that nearly 90% of the nanotubes are semiconductors and thus highly preferential growth of semiconducting over metallic tubes in the PECVD process. Control experiments with other nanotube materials find that HiPco nanotubes consist of ∼61% semiconductors, while laser ablation preferentially grows metallic SWNTs (∼70%). The characterization method used here should also be applicable to assessing the degree of chemical separation of metallic and semiconducting nanotubes.Single-walled carbon nanotubes (SWNTs) have been established as ballistic metallic and semiconducting molecular wires potentially useful for future high performance electronics. 1-4 To realize this potential, it is necessary to achieve preferential growth of semiconducting versus metallic nanotubes or enable high degrees of separation 5-8 of the two types of nanotubes. Here, we present synthesis of high quality SWNTs by a plasma enhanced CVD method at 600°C, and an unexpected result that the PECVD method preferentially grows semiconducting nanotubes at a high percentage of ∼90%. The preferential growth has prompted us to investigate the percentages of semiconducting (s-SWNT) and metallic SWNTs (m-SWNT) in materials grown by other methods, both as control experiments and to elucidate these previously unknown parameters for some of the widely used nanotube materials. We conclude that the relative abundances of semiconducting and metallic nanotubes grown by various methods are different and do not necessarily follow the 2:1 ratio expected for random chirality distribution. Highly preferential growth of a certain type of SWNT can occur depending on the growth method. The results and characterization method presented here should also have implications to chemical separation of nanotubes.A home-built radio frequency (RF, 13.56 MHz) 4-in. remote PECVD system 9 was used for nanotube growth (Figure 1). The plasma discharge source consisted of a copper coil wound around the outside of the 4-in. quartz tube near the feed-gas entrance. We operated the plasma in capacitive mode with the interior furnace wall acting as an electrode and the coil acting as the counter electrode. This created a low-density plasma that propagated down the interior of the quartz tube and reached the sample placed at the center of the tube reactor, 40 cm away from the plasma coil. The

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Separation of Metallic from Semiconducting Single‐Walled Carbon Nanotubes.

Cited by 135 publications

References 1 publication

Parallel arrays of individually addressable single-walled carbon nanotube field-effect transistors

Parallel arrays of individually addressable single-walled carbon nanotube field-effect transistors

Selective suspension in aqueous sodium dodecyl sulfate according to electronic structure type allows simple separation of metallic from semiconducting single-walled carbon nanotubes

Preferential Growth of Semiconducting Single-Walled Carbon Nanotubes by a Plasma Enhanced CVD Method

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