Saturday 16 June 2012

Nano Technology

So what exactly is nanotechnology? One of the problems facing nanotechnology is the confusion about its definition. Most definitions revolve around the study and control of phenomena and materials at length scales below 100 nm and quite often they make a comparison with a human hair, which is about 80,000 nm wide. Some definitions include a reference to molecular systems and devices and nanotechnology 'purists' argue that any definition of nanotechnology needs to include a reference to "functional systems". The inaugural issue of Nature Nanotechnology asked 13 researchers from different areas what nanotechnology means to them and the responses from enthusiastic to sceptical, reflect a variety of perspectives. 




It seems that a size limitation of nanotechnology to the 1-100 nm range, the area where size-dependant quantum effects come to bear, would exclude numerous materials and devices, especially in the pharamaceutical area, and some experts caution against a rigid definition based on a sub-100 nm size.
Another important criteria for the definition is the requirement that the nano-structure is man-made. Otherwise you would have to include every naturally formed biomolecule and material particle, in effect redefining much of chemistry and molecular biology as 'nanotechnology.'
The most important requirement for the nanotechnology definition is that the nano-structure has special properties that are exclusively due to its nanoscale proportions.
We found a good definition that is practical and unconstrained by any arbitrary size limitations :-
 
The design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometer scale (atomic, molecular, and macromolecular scale) that produces structures, devices, and systems with at least one novel/superior characteristic or property.


Mechanical properties of Nanosystems are of interest in the Nanomechanics research. Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macro scale, enabling unique applications. For instance:
  1. Opaque substances become transparent (copper);
  2. Stable materials turn combustible (aluminum);
  3. Insoluble materials become soluble (gold).
  4. A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nano scales.


    Applications of Nanotechnology
    In the modern communication technology traditional analog electrical devices are increasingly replaced by optical or Optoelectronic devices due to their enormous bandwidth and capacity, respectively. Two promising examples are Photonic Crystals and Quantum Dots. Photonic crystals are materials with a periodic variation in the refractive index with a lattice constant that is half the wavelength of the light used. They offer a selectable energy band gap for the propagation of a certain wavelength. Thus they resemble a semiconductor, though not for electrons, but for Photons. Nanolithography is that branch of nanotechnology, which deals with the study and application of fabrication of nanoscale structures like semiconductor circuits. As of 2007, Nanolithography has been is a very active area of research in academia and in industry.
    Quantum Computers use the Laws of Quantum Mechanics for computing fast quantum Algorithms. The Quantum computer has quantum bit memory space termed “Qubit” for several computations at the same time. This facility may improve the performance of the older systems.


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