What is
Nanotechnology?
A basic definition:
Nanotechnology is the engineering of functional systems
at the molecular scale. This covers both current work and
concepts that are more advanced.
In its original
sense, 'nanotechnology' refers to the projected ability to construct items from
the bottom up, using techniques and tools being developed today to make
complete, high performance products.
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In tandem with surface-area effects, quantum
effects can begin to dominate the properties of matter
as size is reduced to the nanoscale. These can affect the
optical, electrical and magnetic behaviour of materials,
particularly as the structure or particle size approaches
the smaller end of the nanoscale. Materials that exploit
these effects include quantum dots, and quantum well
lasers for optoelectronics.
For other materials such as crystalline solids, as the
size of their structural components decreases, there is
much greater interface area within the material; this can
greatly affect both mechanical and electrical properties.
For example, most metals are made up of small
crystalline grains; the boundaries between the grain
slow down or arrest the propagation of defects when
the material is stressed, thus giving it strength. If these
grains can be made very small, or even nanoscale in
size, the interface area within the material greatly
increases, which enhances its strength. For example,
nanocrystalline nickel is as strong as hardened steel.
Understanding surfaces and interfaces is a key challenge
for those working on nanomaterials, and one where
new imaging and analysis instruments are vital.
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