| AVS 64th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology Division | Tuesday Sessions |
| Session NS+EM+MN+PS+SS-TuA |
| Session: | Nano-Photonics, Plasmonics and Mechanics |
| Presenter: | Christopher Wallin, National Institute of Standards and Technology, Center for Nanoscale Science and Technology |
| Authors: | C.B. Wallin, National Institute of Standards and Technology, Center for Nanoscale Science and Technology R. De Alba, NIST/CNST D.A. Westly, NIST/CNST S. Grutzik, Sandia National Laboratories A.T. Zehnder, Cornell University R.H. Rand, Cornell University V.A. Aksyuk, NIST/CNST S. Krylov, Tel Aviv University, Israel B.R. Ilic, NIST/CNST |
| Correspondent: | Click to Email |
Micro- and nano-electromechanical systems (M/NEMS) offer tremendous opportunities for technological advancement in mechanical resonator applications including mass, force and energy sensing, microwave amplification, optomechanics, and energy harvesting. These M/NEMS resonators have many favorable qualities including high mechanical quality factors and compatibility with integrated circuit architectures. More specifically, nonlinear, coupled M/NEMS resonating cantilever arrays have been shown to possess complex system dynamics such as intrinsically localized modes, wave propagation, and sensitivity to defects. The collective behavior of these nonlinear interacting cantilever arrays is remarkably sensitive to the slightest perturbation which makes them an excellent candidate for ultra-sensitive sensors. Moreover, custom device responses can be achieved by tuning the electrostatic fringing field coupling, altering the mechanical coupling via the device’s overhang, or by introducing precisely engineered structural imperfections into the arrays. With our work, we have found that the cantilever arrays exhibit distinct propagation bands, abrupt transitions between standing wave patterns, and synchronization.
Various device geometries including interdigitated arrays, opposing element arrays, and di-element arrays were constructed using both silicon and silicon nitride as device layers. The arrays generally consisted of 100 cantilevers or more which limited boundary effects in the devices. Gold electrodes were patterned on top of the cantilevers for parametric electrical actuation and for fringing field electrostatic coupling between adjacent cantilevers. Mechanical coupling in the arrays was achieved through the large overhangs produced during the device release. The amplitude envelope of the out of plane motion of the cantilevers was captured using a CMOS camera using a frame rate of 30 s-1. The devices were driven electrically and using a piezoelectric transducer under ambient and vacuum conditions. Large, nonlinear vibrational amplitudes were observed in the arrays along with hysteresis. The cantilever arrays exhibited unique standing wave patterns which were sensitive to defects and external loading. Since the dynamics of M/NEMS coupled cantilevers are highly sensitive to local changes in their environment, we envision the practical implementation of coupled arrays for ultra-sensitive chemical, biological, and force sensors in the future.