ABSTRACT
Nanosensors for physical variables such as mass, displacement, force, acceleration and flow measurement are described. Nanogram mass sensing is achieved with a quartz crystal microbalance. MEMS/NEMS resonators are used for attogram and zeptogram mass sensing. Microcantilever resonance frequency and deflection formulae are given; energy dissipation, Q-factor and noise are examined. Doubly clamped and free-free beam resonators are explained. Nanoscale displacement sensors include electron tunneling displacement nanosensor, Coulomb blockade electrometer- and single electron transistor-based nanosensors. Magnetomotive, piezoresistive, piezoelectric and optical nanosensors are also inquired into. Doubly clamped suspended carbon nanotube resonators act as femtonewton force sensors. Suspended CNT electromechanical sensors provide force and displacement measurements. A membrane-based CNT electromechanical sensor is used for determining pressure. Among accelerometers, the tunnel effect accelerometer, the NEMS accelerometer and the silicon nanowire accelerometer are worthy of attention. The working of a CNT flow sensor for ionic solutions is discussed.
