Nanometre
Template:Short description Template:Use dmy dates Template:Cs1 config Template:Infobox unit
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 International System of Units (SI), equal to one billionth (short scale) or one thousand million (long scale) of a meter (0.000000001 m) and to 1000 picometres. One nanometre can be expressed in scientific notation as 1 × 10−9 m and as Template:Sfrac m.
HistoryEdit
The nanometre was formerly known as the "millimicrometre" – or, more commonly, the "millimicron" for short – since it is Template:Sfrac of a micrometer. 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">Template:Cite journal</ref><ref name=":2">Template:Cite journal</ref><ref>Template:Cite book</ref>
EtymologyEdit
The name combines the SI prefix nano- (from the Ancient Greek {{#invoke:Lang|lang}}, {{#invoke:Lang|lang}}, "dwarf") with the parent unit name metre (from Greek {{#invoke:Lang|lang}}, {{#invoke:Lang|lang}}, "unit of measurement").
UsageEdit
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 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.<ref name=":1">Template:Cite journal</ref> 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 semiconductor node, it has also been used to describe typical feature sizes in successive generations of the ITRS Roadmap for miniaturized semiconductor device fabrication in the semiconductor industry.
UnicodeEdit
The CJK Compatibility block in Unicode has the symbol Template:Unichar.