Nanomechanical Motion Transducers for Miniaturized Mechanical Systems

Taejoon Kouh, M. Hanay, Kamil Ekinci
2017 Micromachines  
Reliable operation of a miniaturized mechanical system requires that nanomechanical motion be transduced into electrical signals (and vice versa) with high fidelity and in a robust manner. Progress in transducer technologies is expected to impact numerous emerging and future applications of micro-and, especially, nanoelectromechanical systems (MEMS and NEMS); furthermore, high-precision measurements of nanomechanical motion are broadly used to study fundamental phenomena in physics and biology.
more » ... hysics and biology. Therefore, development of nanomechanical motion transducers with high sensitivity and bandwidth has been a central research thrust in the fields of MEMS and NEMS. Here, we will review recent progress in this rapidly-advancing area. A miniaturized resonator oscillating in one of its modes can be modeled as a one-dimensional damped harmonic oscillator under a time-dependent driving force F(t): (1) Here, x(t) is the modal coordinate, f r is the resonance frequency of the mode, and γ is the dissipation -typically, described in terms of the quality factor, Q = 2π f r /γ. The dissipation experienced by a vibrating nanostructure can come from a variety of sources. Some well-studied examples include clamping losses, thermoelastic damping, and damping from surrounding fluids [12] [13] [14] [15] [16] [17] [18] [19] [20] . Since dissipation (Q-factor) is an important parameter in both fundamental and engineering aspects of miniaturized resonators [21] , there have been attempts to control and enhance Q-factor, for example, via chemical surface treatment [22] , external circuits [23] and parametric amplification [24] . The resonance frequency f r is determined by the geometry-e.g., cantilevered or torsional structures-and the linear dimensions of the device as well as the device material. The stress field within the structure, either intrinsic or induced externally, also affects f r and γ, and can thus be used for tuning [25] [26] [27] .
doi:10.3390/mi8040108 fatcat:pv4cuehs2vcqhpcrdgeknrkuhi