Norio Taniguchi was the first to define the word "nanotechnology" in 1974: Nanotechnology is primarily concerned with the separation, consolidation, and deformation of materials by a single atom or molecule.
- The word "nano" refers to particle and material qualities that are one nanometer to 100 nanometers in size (1 nm is one millionth of a millimeter).
- The DNA double helix has a diameter of 1.8 nm, while a soot particle is 100 nm in size, almost 2,000 times smaller than the full stop at the end of this sentence.
- The nanocosm's structures are therefore substantially smaller than visible light wavelengths (about 380–780 nm).
The nano range is distinguished by three characteristics:
• It is the boundary between quantum physics, which applies to atoms and molecules, and classical rules, which apply to the macro scale. Scientists and engineers can harness quantum phenomena to develop materials with unique features in this intermediate realm. This includes the tunnel effect, which, as indicated in the first chapter, is significant in current transistors.
• When nanoparticles are coupled with other substances, they aggregate a huge number of additional particles around them, which is ideal for scratch-resistant car paints, for example.
• Because surface atoms are more easily pulled away from atomic complexes, nanoparticles function as catalysts for chemical processes when a fracture occurs in the material. This is demonstrated via a simple geometric consideration. A cube with a side of one nanometre (approximately four atoms) includes on average 64 atoms, 56 of which are situated on the surface (87.5 percent). In comparison to bulk atoms, the bigger the particle, the fewer surface atoms accessible for reactions. Only 7.3 percent of the atoms in a nanocube with a side of 20 nm (containing 512,000 atoms) are on the surface. Their percentage declines to 1.2 percent at 100 nm.
Nanoparticles are virtually totally made up of surface, making them extremely reactive and endowing them with surprising mechanical, electrical, optical, and magnetic capabilities.
Physicists have known for a long time that this is true in (quantum) theory. However, the technologies required to isolate and treat materials at the nanoscale have not always been available.
- The invention of the Scanning Tunneling Microscope (STM) by Gert Binning and Heinrich Rohrer in 1981 was a watershed moment in nanotechnology (for which they were awarded the 1986 Nobel Prize in Physics). Single atoms can be seen with this gadget. The electric current between the tip of the grid and the electrically conductive sample reacts extremely sensitively to changes in their spacing as little as one tenth of a nanometer due to a particular quantum phenomena (the tunneling effect).
- In 1990, Donald Eigler and Erhard Schweizer succeeded in transferring individual atoms from point A to point B by altering the voltage provided to the STM grid tip; the device could now not only view but also move individual atoms. With 35 xenon atoms written on a nickel crystal, the two researchers “wrote” the IBM logo. Researchers were able to construct a one-bit memory cell using just 12 atoms twenty-two years later (normal one-bit memory cells still comprise hundreds of thousands of atoms).
What Feynman envisioned as a vision of the future in 1959, namely the atom-by-atom production of exceedingly small goods, is now a reality.
Physicists and engineers are using quantum physics to not only manipulate atoms and create microscopic components, but also to produce new materials (and better comprehend existing ones).
~ Jai Krishna Ponnappan
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