330px, Different lengths as in respect to the molecular scale.">Molecule">molecular scale.
The nanometre (international spelling as used by the
International Bureau of Weights and Measures;
SI symbol: nm) or nanometer (
American spelling) is a
unit
Unit may refer to:
Arts and entertainment
* UNIT, a fictional military organization in the science fiction television series ''Doctor Who''
* Unit of action, a discrete piece of action (or beat) in a theatrical presentation
Music
* ''Unit'' (a ...
of
length in the
International System of Units (SI), equal to one
billionth (
short scale) of a
metre
The metre ( British spelling) or meter ( American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its p ...
() and to 1000
picometres. One nanometre can be expressed in
scientific notation
Scientific notation is a way of expressing numbers that are too large or too small (usually would result in a long string of digits) to be conveniently written in decimal form. It may be referred to as scientific form or standard index form, o ...
as , and as metres.
History
The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is 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.
Etymology
The name combines the
SI prefix
The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. ...
''
nano-'' (from the
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
, ', "dwarf") with the parent unit name ''metre'' (from Greek , ', "unit of measurement").
Usage
Nanotechnologies are based on phenomena typically occurring on a scale of nanometres (see
nanoscopic scale).
The nanometre is often used to express dimensions on an atomic scale: the diameter of a
helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
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
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...
of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible ...
near the visible part of the
spectrum
A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of color ...
: visible light ranges from around 400 to 700 nm.
[Hewakuruppu, Y., et al., ]
Plasmonic " pump – probe " method to study semi-transparent nanofluids
', Applied Optics, 52(24):6041-6050 The
ångström, which is equal to 0.1 nm, was formerly used for these purposes.
Since the late 1980s, in usages such as the
32 nm and the
22 nm
The 22 nm node is the process step following 32 nm in CMOS MOSFET semiconductor device fabrication. The typical half-pitch (i.e., half the distance between identical features in an array) for a memory cell using the process is around 22 nm. ...
semiconductor node, it has also been used to describe typical feature sizes in successive generations of the
ITRS Roadmap for miniaturized
semiconductor device fabrication
Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically integrated circuit (IC) chips such as modern computer processors, microcontrollers, and memory chips such as NAND flash and DRAM that are pres ...
in the
semiconductor industry
The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors and semiconductor devices, such as transistors and integrated circuits. It formed around 1960, once the fabrication of semico ...
.
Unicode
The
CJK Compatibility block in
Unicode
Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...
has the symbol .
References
External links
Near-field Mie scattering in optical trap nanometry
{{SI units of length
Metre
