Modeling the mechanical vibration and current flow in carbon nanotubes

This thesis investigates the application of carbon nanotubes (CNT) for sensing and transduction of time varying signals in the radio frequency band. A computational method is proposed to model the mechanical vibrations of the CNT that is excited by an incident electromagnetic field. The Euler-Bernoulli beam model is applied to a doubly clamped CNT connected between source and drain terminals and embedded in a trench above a substrate that serves as the gate. The Chebyshev-Galerkin method is used as a solution approach for computing the transverse displacement and velocity of the CNT set into motion. The displacement calculation is applied to compute charge transport that results from the mechanical vibrations. The CNT functions as a semiconducting channel of a field-effect transistor. A semiclassical model is applied to calculate the current flow as a function of the drain and gate potentials. An application of the CNT as a detector and demodulator for amplitude modulated signals is demonstrated. These features may be applied in the design of tunable sensors that can adaptively scan a selected range of radio frequencies and generate signatures that can be used to detect the presence of active radio transmitters in the frequency bands.