NANOELECTROMECHANICAL SYSTEMS

摘要

Nanoelectromechanical systems, or NEMS, are MEMS scaledrnto submicron dimensions [1]. In this size regime, it is possible tornattain extremely high fundamental frequencies whilernsimultaneously preserving very high mechanical responsivityrn(small force constants). This powerful combination of attributesrntranslates directly into high force sensitivity, operability atrnultralow power, and the ability to induce usable nonlinearity withrnquite modest control forces. In this overview I shall provide anrnintroduction to NEMS and will outline several of their excitingrninitial applications. However, a stiff entry fee exists at thernthreshold to this new domain: new engineering is crucial tornrealizing the full potential of NEMS. Certain mainstays in thernmethodology of MEMS will, simply, not scale usefully into thernregime of NEMS. The most problematic of issues are the size ofrnthe devices compared to their embedding circuitry, their extremernsurface-to-volume ratios, and their unconventional “characteristicrnrange of operation”. These give rise to some of the principalrncurrent challenges in developing NEMS. Most prominent amongrnthese are the need for: ultrasensitive, very high bandwidthrndisplacement transducers; an unprecedented control of surfacernquality and adsorbates; novel modes of efficient actuation at thernnanoscale, and precise, robust, and routinely reproducible newrnapproaches to surface and bulk nanomachining. In what follows Irnshall attempt to survey each of these aspects in turn, but willrnconclude by describing some exciting prospects in this new field.