Charge transfer in nano-electromechanical systems

In this thesis I experimentally investigated electromechanical behavior of nanostructures with the focus on the interaction between field emission and mechanical motion of the nanopillars operating in the radio frequency regime, where a strong electromechanical coupling is dominant. The typical device we have studied here is a system with a nanopillar in between two electrode gates, machined in silicon-on-insulator material. The actuation of the pillar was accomplished by resonant Coulomb force excitation: a combination of the capacitive force and Coulomb force onto the excess charge being present on the Au island on top of the nanopillar. When the driving ac signal matches the mechanical eigenfrequency of the device, resonant motion of nanopillar is achieved.; I have studied electron field emission properties and mechanical mixing of two electromagnetic signals in a free-standing silicon pillar nanostructure mechanically oscillating in between two facing electrodes. The nanopillar allows for mechanical clocking of the field emitted electrons. We found that the current amplitude can be tuned as an effect of the emitting current induced by a superimposed do bias. In this setup field emission and frequency mixing are controlled by both the voltage bias and the mechanical oscillations of the pillar. The interaction is modeled on the basis of finite element modeling.; Moreover, I investigated the DC driven mechanical mixing properties of the nanopillar structure by forcing it into resonance. This was achieved by application of a DC bias and a single AC frequency signal in the nonlinear IV-characteristic field emission regime. Finally, we demonstrated the detection method of self excitation from the nanopillars driven by an applied DC bias with the help of signal mixing.; Still many properties of the shuttle systems remain to be investigated. One logical extension of the experiments is to investigate the behavior of charge transport through arrays of nanopillars for nanomechanical computing (NMC) devices.