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CNT-based Sensors

Carbon nanotube based electronic devices, such as field effect transistors, can be used as very sensitive sensors. We have developed a theoretical model to analyze how the conductivity of a CNT-FET is affected by the electrochemical environment. Colleagues at DuPont have shown that this technique can be used to develop very sensitive biosensors.

 

 

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Boussaad & Diner (DuPont)

This figure shows an experimental set-up for and electrochemical CNT-FET sensor. 'S' and 'D' are electrodes connected by the CNT's. 'G' is a gate electrode in the plane of the wafer. Other electrodes are relatively massive and allow one to control where the potential drop between the nanotube and the gate electrode occurs.


 

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The figure above represents our model for the CNT-FET device in the presence of redox species in solution around it.

(Tian Tang)

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The figure above shows calculated conductance as a function of gate voltage for different ratios of oxidizing and reducing species. It correctly captures the fact that change of this ratio causes a horizontal shift in the response of the device.

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“Model for Modulation of Conductance in a Carbon Nanotube Field Effect Transistor by Electrochemical Gating”, Tian Tang and Anand Jagota, Journal of Computational and Theoretical Nanotechnology , submitted (2007).