Frequency and Q factor control of nanomechanical resonators

We present an integrated scheme for dielectric drive and read-out of high-Q nanomechanical resonators that enable tuning of both the resonance frequency and quality factor with an applied dc voltage. A simple model for altering these quantities is derived, incorporating the resonator's complex electric polarizability and position in an inhomogeneous electric field, which agrees very well with experimental findings and finite element simulations. Comparing two sample geometries demonstrates that careful electrode design determines the direction of frequency tuning of flexural modes of a string resonator. Furthermore, we show that the mechanical quality factor can be voltage reduced sixfold. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751351]