Radio-frequency characterization of varactors based on carbon nanotube arrays

Ek-Weis, Johan; Eriksson, Anders; Idda, Tonio; Olofsson, Niklas; Campbell, Eleanor E. B.

doi:10.1243/17403499jnn122

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…This was found to give an order of magnitude lower resistivity than electron-beam evaporated Mo thin films of the same thickness. The value of the capacitance for a given actuation voltage was found by measuring the S-parameters in the range from 200 MHz to 1.5 GHz by using a probe station connected to an Agilent E5071B network analyzer [11]. The shield electrodes were connected to ground during the measurements to form a coplanar ground-signal-ground (GSG) to fit GSG probes.…”

Section: Fabrication and Measurement Setupmentioning

confidence: 99%

Determination of the effective Young’s modulus of vertically aligned carbon nanotube arrays: a simple nanotube-based varactor

et al. 2009

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The electromechanical properties of arrays of vertically aligned multiwalled carbon nanotubes were studied in a parallel plate capacitor geometry. The electrostatic actuation was visualized using both optical microscopy and scanning electron microscopy, and highly reproducible behaviour was achieved for actuation voltages below the pull-in voltage. The walls of vertically aligned carbon nanotubes behave as solid cohesive units. The effective Young's modulus for the carbon nanotube arrays was determined by comparing the actuation results with the results of electrostatic simulations and was found to be exceptionally low, of the order of 1-10 MPa. The capacitance change and Q-factor were determined by measuring the frequency dependence of the radio-frequency transmission. Capacitance changes of over 20% and Q-factors in the range 100-10 were achieved for a frequency range of 0.2-1.5 GHz.

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Section: Fabrication and Measurement Setupmentioning

confidence: 99%

Determination of the effective Young’s modulus of vertically aligned carbon nanotube arrays: a simple nanotube-based varactor

et al. 2009

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“…Moreover, they naturally have narrow bandwidth that could be beneficial to measure the small changes that acid ions produce in signals. The most studied and simple parameters are scattering parameters, from which the dielectric properties can be derived [56][57][58][59][60][61].…”

Section: Introductionmentioning

confidence: 99%

A contactless characterization of CNT/Epoxy nanocomposites behavior under acid exposure

Tamayo-Vegas

Lafdi

Elsdon

2023

Composite Structures

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“…37 The aim of this work is to give a general assessment of carbon based NEMS varactors and to validate their potential using an analytical model developed here, as well as published experimental data. [38][39][40][41][42][43] Since carbon based varactors are still in emergence, this review focuses on their potential advantages and remaining challenges. First, a short review of existing varactor technologies is given.…”

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confidence: 99%

Vertically aligned carbon based varactors

Ghavanini

Enoksson

Bengtsson

et al. 2011

Journal of Applied Physics

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This paper gives an assessment of vertically aligned carbon based varactors and validates their potential for future applications. The varactors discussed here are nanoelectromechanical devices which are based on either vertically aligned carbon nanofibers or vertically aligned carbon nanotube arrays. A generic analytical model for parallel plate nanoelectromechanical varactors based on previous works is developed and is used to formulate a universal expression for their voltage-capacitance relation. Specific expressions for the nanofiber based and the nanotube based varactors are then derived separately from the generic model. This paper also provides a detailed review on the fabrication of carbon based varactors and pays special attention to the challenges in realizing such devices. Finally, the performance of the carbon based varactor is assessed in accordance with four criteria: the static capacitance, the tuning ratio, the quality factor, and the operating voltage. Although the reported performance is still far inferior to other varactor technologies, our prognosis which stems from the analytical model shows a promise of a high quality factor as well as a potential for high power handling for carbon based varactors.

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Radio-frequency characterization of varactors based on carbon nanotube arrays

Cited by 4 publications

References 9 publications

Determination of the effective Young’s modulus of vertically aligned carbon nanotube arrays: a simple nanotube-based varactor

Determination of the effective Young’s modulus of vertically aligned carbon nanotube arrays: a simple nanotube-based varactor

A contactless characterization of CNT/Epoxy nanocomposites behavior under acid exposure

Vertically aligned carbon based varactors

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