View source for Nanometre

{{short description|Unit of length}}
{{use dmy dates|date=August 2024}}
{{cs1 config|name-list-style=vanc }}
{{Infobox unit
| name = nanometre
| image    = Chiraltube.png
| caption  = One nanometric [[carbon nanotube]], photographed with [[scanning tunneling microscope|scanning tunnelling microscope]]
| symbol   = nm
| standard = [[SI]]
| quantity = [[length]]
| units1   = [[SI units]]
| inunits1 = {{val|1|e=-9|ul=m}}<br /><!--
    -->&emsp;&emsp;&emsp;{{val|1|e=3|ul=pm}}
| units2   = [[Natural units]]
| inunits2 = {{val|6.1877|e=25|u={{math|[[Planck length|<var>ℓ</var><sub>P</sub>]]}}}}<br /><!--
    -->&emsp;{{val|18.897|u=[[Bohr radius|''a''<sub>0</sub>]]}}
| units3   = [[imperial units|imperial]]/[[US customary units|US]]&nbsp;units
| inunits3 = {{convert|1|nm|in|disp=out|lk=on|sigfig=5}}
}}
[[file:EM Spectrum Properties edit.svg|thumb|330px|Different lengths as in respect to the [[electromagnetic spectrum]], measured by the metre and its derived scales. The nanometre is often used to express dimensions on an atomic scale and mostly in the [[Molecule|molecular]] scale.]]
The '''nanometre''' (international spelling as used by the [[International Bureau of Weights and Measures]]; [[SI]] symbol: '''nm'''), or '''nanometer''' ([[American and British English spelling differences#-re, -er|American spelling]]), is a [[units of measurement|unit]] of [[length]] in the International System of Units (SI), equal to one [[billionth]] ([[short scale]]) or one thousand million (long scale) of a [[metre]] (0.000000001&nbsp;m) and to 1000&nbsp;[[picometre]]s. One nanometre can be expressed in [[scientific notation]] as 1 × 10<sup>−9</sup>&nbsp;m and as {{sfrac|{{val|1,000,000,000}}}}&nbsp;m.

==History==
The nanometre was formerly known as the "''millimicrometre''"&nbsp;– or, more commonly, the "''millimicron''" for short&nbsp;– since it is {{sfrac|1000}} of a [[micrometre]]. It was often denoted by the symbol ''mμ'' or, more rarely, as ''μμ'' (however, ''μμ'' should refer to a ''millionth'' of a micron).<ref name=":0">{{Cite journal |first1=The |last1=Svedberg |first2=J. Burton |last2=Nichols |title=Determination of the size and distribution of size of particle by centrifugal methods |journal=Journal of the American Chemical Society |year=1923 |volume=45 |issue=12 |pages=2910–2917 |doi=10.1021/ja01665a016 }}</ref><ref name=":2">{{Cite journal |first1=The |last1=Svedberg |first2=Herman |last2=Rinde |title=The ulta-centrifuge, a new instrument for the determination of size and distribution of size of particle in amicroscopic colloids |journal=Journal of the American Chemical Society |year=1924 |volume=46 |issue=12 |pages=2677–2693 |doi=10.1021/ja01677a011 }}</ref><ref>{{Cite book |first=Karl |last=Terzaghi |author-link=Karl von Terzaghi|title=Erdbaumechanik auf bodenphysikalischer Grundlage |publisher=Franz Deuticke |location=Vienna |year=1925 |page=32 }}</ref>

==Etymology==
The name combines the [[SI prefix]] ''[[nano-]]'' (from the [[Ancient Greek]] {{lang|grc|νάνος}}, ''{{lang|grc-Latn|nanos}}'', "dwarf") with the parent unit name ''metre'' (from Greek {{lang|grc|μέτρον}}, ''{{lang|grc-Latn|metron}}'', "unit of measurement").

==Usage==
[[Nanotechnology|Nanotechnologies]] are based on physical processes which occur on a scale of nanometres (see [[nanoscopic scale]]).<ref name=":0" />

The nanometre is often used to express dimensions on an atomic scale: the diameter of a [[helium]] atom, for example, is about 0.06&nbsp;nm, and that of a [[ribosome]] is about 20&nbsp;nm. The nanometre is also commonly used to specify the [[wavelength]] of [[electromagnetic radiation]] near the visible part of the [[electromagnetic spectrum|spectrum]]: visible light ranges from around 400 to 700&nbsp;nm.<ref name=":1">{{cite journal |first=Yasitha L. |last=Hewakuruppu |first2=Leonid A. |last2=Dombrovsky |first3=Chuyang |last3=Chen |first4=Victoria |last4=Timchenko |first5=Xuchuan |last5=Jiang |first6=Sung |last6=Baek |first7=Robert A. |last7=Taylor  |url=https://www.researchgate.net/publication/257069746 |title=Plasmonic " pump – probe " method to study semi-transparent nanofluids |journal=Applied Optics |date=2013 |volume=52 |issue=24 |pages=6041–6050|doi=10.1364/AO.52.006041 |pmid=24085009 |bibcode=2013ApOpt..52.6041H }}</ref> The [[ångström]], which is equal to 0.1&nbsp;nm, was formerly used for these purposes.

Since the late 1980s, in usages such as the [[32 nanometer|32&nbsp;nm]] and the [[22 nanometer|22&nbsp;nm]] [[semiconductor node]], it has also been used to describe typical feature sizes in successive generations of the [[International Technology Roadmap for Semiconductors|ITRS Roadmap]] for miniaturized [[semiconductor device fabrication]] in the [[semiconductor industry]].

==Unicode==
The [[CJK Compatibility]] block in [[Unicode]] has the symbol {{unichar|339A|SQUARE NM}}.

==References==
{{Reflist}}

==External links==
{{Wiktionary|nanometre}}

*[http://adsabs.harvard.edu/abs/2001SPIE.4434..158G Near-field Mie scattering in optical trap nanometry]

{{SI units of length}}

[[Category:Metre]]
[[Category:Units of length]]