INTRODUCTION
The development and deployment of NEMS and MEMS are critical to theU.S. economy and society because nano- and microtechnologies will lead to major breakthroughs in information technology and computers, medicine and health, manufacturing and transportation, power and energy systems, and avionics and national security. NEMS and MEMS have important impacts in medicine and bioengineering (DNA and genetic code analysis and synthesis, drug delivery, diagnostics, and imaging), bio and information technologies, avionics, and aerospace (nano- and microscale actuators and sensors, smart reconfigurable geometry wings and blades, space-based flexible structures, and microgyroscopes), automotive systems and transportation (sensors and
actuators, accelerometers), manufacturing and fabrication, public safety, etc.
During the last years, the government and the high-technology industry have heavily funded basic and applied research in NEMS and MEMS due to the current and potential rapidly growing positive direct and indirect social and economic impacts. Nano- and microengineering are the fundamental theory, engineering practice, and leading-edge technologies in analysis, design, optimization, and fabrication of NEMS and MEMS, nano- and microscale structures, devices,
and subsystems. The studied nano- and microscale structures and devices have dimensions of nano- and micrometers. To support the nano- and microtechnologies, basic and applied research and development must be performed. Nanoengineering studies nano- and microscale-size materials and structures, as well as devices and systems, whose structures and components exhibit novel physical (electromagnetic and electromechanical), chemical, and biological properties, phenomena, and processes. The dimensions of nanosystems and their components are 10-10 m (molecule size) to 10-7 m; that is, 0.1 to 100 nanometers. Studying nanostructures, one concentrates one’s attention on the atomic and molecular levels, manufacturing and fabrication, control and dynamics, augmentation and structural integration, application and large-scale system synthesis, ect.
Reducing the dimensions of systems leads to the application of novel materials (carbon anotubes, quantum wires and dots). The problems to be solved range from mass-production and assembling (fabrication) of nanostructures at the atomic/molecular scale (e.g., nanostructured electronics and actuators/sensors) with the desired properties. It is essential to design novel nanodevices such as nanotransistors and nanodiodes, nanoswitches and nanologic gates, in order
to design nanoscale computers with terascale capabilities. All living biological systems function due to molecular interactions of different subsystems. The molecular building blocks (proteins and nucleic acids, lipids and carbohydrates, DNA and RNA) can be viewed as inspiring possible strategy on how to design high-performance NEMS and MEMS that possess the properties and characteristics needed. Analytical and numerical methods are available to analyze the dynamics and three-dimensional geometry, bonding, and other features of atoms and molecules. Thus, electromagnetic and mechanical, as well as other physical and chemical properties can be studied.
Nanostructures and nanosystems will be widely used in medicine and health. Among possible applications of nanotechnology are: drug synthesis and drug delivery (the therapeutic potential will be enormously enhanced due to direct effective delivery of new types of drugs to the specified body sites),
Nanosurgery and nanotherapy, genome synthesis and diagnostics, nanoscale actuators and sensors (disease diagnosis and prevention), nonrejectable nanoartificial organs design and implant, and design of high-performance nanomaterials.
It is obvious that nano- and microtechnologies drastically change the fabrication and manufacturing of materials, devices, and systems through:
1.predictable properties of nano composites and materials (e.g., light weight and high strength, thermal stability, low volume and size, extremely high power, torque, force, charge and current densities, specified thermal conductivity and resistivity, et cetera),
2.virtual prototyping (design cycle, cost, and maintenance reduction),
3.improved accuracy and precision, reliability and durability,
4.higher degree of efficiency and capability, flexibility and integrity, supportability and affordability, survivability and redundancy,
5.improved stability and robustness,
6.higher degree of safety,
7.environmental competitiveness.
Foreseen by Richard Feyman, the term “nanotechnology” was first used by N. Taniguchi in his 1974 paper, "On the basic concept of nanotechnology." In the last two decades, nanoengineering and nanomanufacturing have been popularized by Eric Drexler through the Foresight Institute.
Advancing miniaturization towards the molecular level with the ultimate goal to design and manufacture nanocomputers and nanomanipulators (nanoassemblers), large-scale intelligent NEMS and MEMS (which have nanocomputers as the core components), the designer faces a great number of unsolved problems.
Possible basic concepts in the development of nanocomputers are listed below. Mechanical “computers” have the richest history traced thousand years back. While the most creative theories and machines have been developed and demonstrated, the feasibility of mechanical nanocomputers is questioned by some researchers due to the number of mechanical
components (which are needed to be controlled), as well as due to unsolved
manufacturing (assembling) and technological difficulties. Chemical nanocomputers can be designed based upon the processing information by making or breaking chemical bonds, and storing the information in the resulting chemical. In contrast, in quantum nanocomputers, the information can be represented by a quantum state (e.g., the spin of the atom can be
controlled by the electromagnetic field).
Electronic nanocomputers can be designed using conventional concepts tested and used for the last thirty years. In particular, molecular transistors or quantum dots can be used as the basic elements. The nanoswitches (memoryless processing elements), logic gates, and registers must be manufactured on the scale of a single molecule. The so-called
quantum dots
are metal boxes that hold the discrete number of electrons which is changed applying the electromagnetic field. The quantum dots are arranged in the quantum dot cells. Consider the quantum dot cells which have five dots and two quantum dots with electrons. Two different states are illustrated in figure
(the dashed dots contain the electron, while the white dots do not contain the electron). It is obvious that the quantum dots can be used to synthesize the logic devices. Figure. Quantum dots with states “0” and “1”, and “1 1” configuration It was emphasized that as conventional electromechanical systems, nanoelectromechanical systems (actuators and other molecular devices) are controlled by changing the electromagnetic field. It becomes evident that other nanoscale structures and devices (nanodiodes and nanotransistors) are also controlled by applying the electromagnetic field (recall that the voltage and current result due to the electromagnetic field).
Sergey Edward Lyshevski
CRC Press