Nanometre

The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American spelling) is a unit of length in the metric system, equal to one billionth (short scale) of a metre (0.000000001 m). One nanometre can be expressed in scientific notation as 1×10−9 m, in engineering notation as 1 E−9 m, and as simply 1/1000000000 metres.

This article is about the unit of length. For semiconductor nodes, see Semiconductor device fabrication.
Nanometre
Unit systemmetric
Unit oflength
Symbolnm 
Conversions
1 nm in ...... is equal to ...
   SI units   1×10−9 m
   1×103 pm
   Natural units   6.1877×1025 ℓP
 18.897 a0
   imperial/US units   3.2808×10−9 ft
   3.9370×10−8 in

History

The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is 1/1000 of a micron (micrometre), and was often denoted by the symbol mµ or (more rarely and confusingly, since it logically should refer to a millionth of a micron) as µµ.[1][2][3]

Etymology

The name combines the SI prefix nano- (from the Ancient Greek νάνος, nanos, "dwarf") with the parent unit name metre (from Greek μέτρον, metrοn, "unit of measurement").

When used as a prefix for something other than a unit of measure (as in "nanoscience"), nano refers to nanotechnology, or phenomena typically occurring on a scale of nanometres (see nanoscopic scale).[1]

Usage

The nanometre is often used to express dimensions on an atomic scale: the diameter of a helium atom, for example, is about 0.06 nm, and that of a ribosome is about 20 nm. The nanometre is also commonly used to specify the wavelength of electromagnetic radiation near the visible part of the spectrum: visible light ranges from around 400 to 700 nm.[4] The ångström, which is equal to 0.1 nm, was formerly used for these purposes, but is still used in other fields.

Since the late 1980s, in usages such as the 32 nm and the 22 nm semiconductor node, it has also been used to describe typical feature sizes in successive generations of the ITRS Roadmap for miniaturization in the semiconductor industry.

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See also

References
  1. Svedberg, The; Nichols, J. Burton (1923). "Determination of the size and distribution of size of particle by centrifugal methods". Journal of the American Chemical Society. 45 (12): 2910–2917. doi:10.1021/ja01665a016.
  2. Svedberg, The; Rinde, Herman (1924). "The ulta-centrifuge, a new instrument for the determination of size and distribution of size of particle in amicroscopic colloids". Journal of the American Chemical Society. 46 (12): 2677–2693. doi:10.1021/ja01677a011.
  3. Terzaghi, Karl (1925). Erdbaumechanik auf bodenphysikalischer Grundlage. Vienna: Franz Deuticke. p. 32.
  4. Hewakuruppu, Y., et al., Plasmonic " pump – probe " method to study semi-transparent nanofluids, Applied Optics, 52(24):6041-6050


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