We focus on the exploration of NEM-physics and the development of NEM-devices that can be used as extremely sensitive sensors for force and mass detection down to the single molecule level, as high-frequency resonators up to the GHz range, or as ultra-fast, low-power switches. Both a top-down and bottom-up approach is followed. The top-down approach consists of scaling down the existing micron-size MEMS technology far into the sub-100 nm range. In the bottom-up approach suspended structures of single-walled carbon nanotubes and of (semiconducting) nanowires are fabricated. In particular, (new) mechanisms for detection of displacements and eigenfrequencies are studied with the goal to reveal the physical processes (e.g. damping, thermal effects, momentum noise) that limit the sensitivity of the devices. Novel optical and magnetic detection schemes need to be investigated.

The search for the limits of mechanical motion is a central theme. At low temperature, quantum friction starts to limit the Q-factor and vibrating NEM-devices are limited by zero-point motion. This quantum limitation poses an ultimate limit to sensitivity of NEM-devices. In addition, other quantum phenomena are expected to be present. Quantum optics-like experiments with phonons, phonon lasers or quantum-tunnelling experiments with massive objects (strained suspended nanotubes placed between two gate electrodes) are just a few examples. As the size of NEM-devices shrinks down, electron-phonon coupling translates into an increasingly strong interplay between electrical and mechanical degrees of freedom. Device operation results in charge distributions that are inhomogeneous on the nanometer scale, giving rise to Coulomb forces that are strong enough to change device geometry. The classical theory of elasticity breaks down and the regime of quantum elasticity has been entered.