Nano electromechanical systems are devices that operate like normal electromechanical devices but are built on the nanoscale or even the atom scale. Controlling and building such devices require advanced technology that is still facing a lot of challenges
Nanotechnology is defined by the National Nanotechnology initiative as "understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale."
The importance of nanoscale technology is the idea that all properties of material up o the atoms can be used.
Nanoelectromechanical systems, also known as "NEMS", are basically electro mechanical systems such as switches and transistors that are scaled to nano or even atom size . Nanoelectromechanical systems are evolving, with new scientific studies and technical applications. In general, all mechanical devices are shrinking in thickness and width to reduce mass, this is needed to reduce mass and lower the force constants of these systems. The main advantage of Nanoelectromechanical systems is that its flexible properties allow it to access to fundamental frequencies in the microwave range which vary from 0.3GHz to 300GHz. Another advantage is the high mechanical quality factor `Q' which can easily be in the tens of thousands or higher; another advantage is the active masses in the femtogram range which is A unit of mass equal to 10^15 grams and use a simple fg. In addition to this nanoelectromechanical systems have force sensitivities at the attonewton level; mass sensitivity at the level of _individual_ molecules, heat capacities far below a "yoctocalorie" .
Even though this science is still growing, it is still under experiments to find methods of build and control such systems...