Radio-frequency transmission characteristics of a multi-walled carbon nanotube

Jun, Seong Chan; Choi, June-Whan; N, S; Baik, Chan Wook; Lee, Sanghyo; Kim, H. Jin; Hone, James; Kim, J M

doi:10.1088/0957-4484/18/25/255701

Cited by 44 publications

(30 citation statements)

References 21 publications

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“…For our 25 mm long lines we calculate the electrical length to be 1.9 at 10 GHz which is clearly much longer than 0.05. By contrast, in the study by Jun et al 15 the CNT was 7 m long and at 50 GHz, we calculate that the electrical length in that study to be 0.0027 -safely well below the 0.05limit. Even with this limitation in mind it is still worth considering the composition of the composite from an electrical point of view.…”

contrasting

confidence: 51%

“…13 This discrete circuit component approach has been previously successfully applied to electrode geometries consisting of a number of single nanotube or small bundles of nanotubes. 14,15 However, the approach is not valid when the S-parameters are extracted from long conductors. It is 5 known that for the conventional transmission line equations to be valid the electrical length of the conductor should be no more than about 1/20 of the signal wavelength.…”

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confidence: 99%

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Electrical performance of carbon nanotube-polymer composites at frequencies up to 220 GHz

Alshehri

Jakubowska

Słoma

et al. 2011

Applied Physics Letters

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We have measured the sub-THz electrical response of screen printed carbon nanotube -poly(methyl methacrylate) polymer composites up to 220 GHz. The measured electrical losses using mm long coplanar waveguide geometries averaged as low as 0.15 dB/mm in the frequency range 40 GHz to 110GHz and showed a reduction in signal loss with increasing frequency; a behaviour opposite to that found in conventional metallic conductors. Between 140 and 220 GHz the electrical losses averaged 0.28 dB/mm. We show that the low electrical losses are associated with the capacitive coupling between the nanotubes and discuss potential high frequency applications. *Corresponding authors: A.Alshehri@surrey.ac.uk (Ali Alshehri) and David.Carey@surrey.ac.uk (J David Carey) 2 Carbon nanotube (CNT) electronics has firmly established itself as one of the most important areas of modern nanoelectronics. 1, 2 The suppression of carrier backscattering brought about by the nanotube's band structure results in long mean free paths leading to ballistic transport and opens up the possibility of GHz and sub-THz applications. 3 Tailoring the intrinsic electronic properties of the CNT by choosing semiconducting or metallic CNTs has already led to the fabrication of field effect transistors 3 and sensors 4 for the former type of nanotube and interconnects 5 and field emission materials 6 for the latter.Previous high frequency studies of CNTs have tended to concentrate on employing small (micron) electrode gaps, often making use of single or few singlewalled nanotube bundles as the active elements in a transistor architecture. 3 Chemical vapor deposited (CVD) carbon nanotubes bundles 7 , vertically aligned arrays 8 or nanotube ropes 9 for possible applications as electrical interconnects have also been variously explored. However such measurements using short CNTs bundles are often affected by the presence of parasitic capacitances associated with the electrodes and the presence of large impedance mismatches.Electrode architectures for transistors and interconnect applications imposes strict requirements for the environment that the nanotube can be found. Using a CNT composite frees up many of these constraints and at high frequency opens up the possibility of using large area, high bandwidth CNT electronics for communications, microwave and surface acoustic wave devices. In this Letter we have successfully characterised up to 25 mm long CNT -poly(methyl methacrylate) polymer composites up to 220 GHz. We show that the frequency response of the composites is significantly different from that of conventional metallic conductors and that capacitive coupling between the nanotubes plays an important role in the ac conduction.The samples characterised consisted of CVD grown multiwalled CNTs (average length 1.5 m, average diameter 9.5 nm, Nanocyl batch number NC3100) mixed with poly(methyl-methacrylate) (PMMA) to produce composites with 10 wt.% CNT loading. Apart from its ready availability and compatibility with high frequency electronics, PMMA was chose...

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confidence: 51%

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confidence: 99%

Electrical performance of carbon nanotube-polymer composites at frequencies up to 220 GHz

Alshehri

Jakubowska

Słoma

et al. 2011

Applied Physics Letters

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“…This discrete circuit component approach has been previously successfully applied to electrode geometries consisting of a number of nanoconductors such as single carbon nanotubes (CNTs) or small bundles of nanotubes 21 .…”

Section: Resultsmentioning

confidence: 99%

Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications

Alshehri

Jakubowska

Machová

et al. 2012

ACS Appl. Mater. Interfaces

153

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An enhancement in the electrical performance of low temperature screen-printed silver nanoparticles (nAg) has been measured at frequencies up to 220 GHz. We show that for frequencies above 80 GHz the electrical losses in coplanar waveguide structures fabricated using nAg at 350 o C are lower than those found in conventional thick film Ag conductors consisting of micron-sized grains and fabricated at 850 o C. The improved electrical performance is attributed to the better packing of the silver nanoparticles resulting in lower surface roughness by a factor of three. We discuss how the use of silver nanoparticles offers new routes to high frequency applications on temperature sensitive conformal substrates and in sub-THz metamaterials.

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“…For MWCNTs grown by CVD (15 nm diameter), typical resistances of ~40 kΩ/μm were measured, while resistances of electroless deposited Ni contacts were estimated to be ~10 kΩ per contact (Liebau et al, 2003). In another work, for PE-CVD grown MWCNTs (25 nm diameter, 5μm long) considerably lower resistances (< 10 kΩ/μm) were measured using a 2-point method and Nb electrodes deposited by evaporation (contact resistances were not estimated) (Jun et al, 2007). In our studies , similar values were obtained for low-bias contact resistances using CVD grown MWCNTs (30 nm mean www.intechopen.com diameter): ~20 kΩ per Pd or Ni electroless contacts.…”

Section: Measurements Of Cnt Resistancesmentioning

confidence: 98%

“…Bundles of SWCNTs were shown to have potentially superior performance at smaller leghths (<1 μm), however for this, dense nanotube packing is essencial which is a very difficult practical task. Recently, it has been reported by Jun et al, 2007, that the AC conductance of high quality PECVD (plasma enhanced chemical vapor deposition) grown MWCNTs decreases gradually with increasing frequency (frequencies up to 50 GHz were studied), indicating that nanotubes can be used not only for DC but also in a microwave range.…”

Section: Electrical Properties Of Carbon Nanotubesmentioning

confidence: 99%