Semiconductor Quantum Electromechanical Structures

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One of the meet important results we obtained is the realization of on-chip micromechanical parametric resonator based on semiconductor heterostructures. We proposed the application to the basic device for a nanomechanical parametron computer and demonstrated one bit operation. Because the energy dissipation in the micro/nanomechanical resonator is extremely small, the nanomechanical parametron computer can be a highly power-efficient digital processing system. We also successfully demonstrate this parametric resonator can be used for parametric signal amplification and very sensitive charge sensors.It is also a very important result that the vibration damping in semiconductor-based micromechanical resonator was controlled by carrier excitation. So far the damping control was performed by coupling the micromechanical resonator to optical cavity, which needs fine alignment of optics. In our new method, the fine tuning was made by laser wavelength adjustment, and we found that significan … More t effects can be obtained at around the band gap wavelength. This indicates that the effect was caused by the carrier excitation and piezoelectric effects play important role. By making the effective damping negative, we also successfully realized self oscillation of mechanical cantilever.Furthermore, the Micromechanical beam resonators were fabricated using a strained film grown on a relaxed In_0.1Ga_0.9As/In_0.1Al_0.9As buffer layers. The natural frequency of fundamental mode was increased by the applied tensile strain. In addition, nearly one-order of magnitude sharper resonance line shape was obtained for the best sample. This technique can be widely applied for improving the performance of resonator-based micro/nanoelectromechamcal devices.We also made development of fabrication and measurement technique for semiconductor electromechanical devices, including 3D nanohthography, block co-polymer lithography, quantum dot electrometiy, nanoprobe technique, semiconductor nanowire growth. Although, they could not be integrated with electromechanical systems, they are promising for future detailed study of quantum electromechanical systems. Less