impurityn.
/ɪmˈpjʊərɪti/ 1. The quality or condition of being impure or of containing something foul or unclean; concrete foul or offensive matter, dirt.
ΘΚΠ
the world > physical sensation > cleanness and dirtiness > dirtiness > pollution or defilement > [noun] > polluted or defiled condition
sulliedness1571
impurity1598
defiledness1607
dregginess1608
drossiness1638
feculency1651
feculence1733
branfulness1879
1598 A. M. tr. J. Guillemeau Frenche Chirurg. 11 b/1 The matter, and all impuritye might therout have free passage.
1660 F. Brooke tr. V. Le Blanc World Surveyed 14 By reason of the impurity of the ayr, there is scarce any more then these two townes in the whole country.
1797 R. Beilby & T. Bewick Hist. Brit. Birds I. 206 The Redbreast..beats it [a worm] till the inward part comes away; then..cleanses it from all its impurities, eating only the..skin.
1806 Med. & Physical Jrnl. 15 547 Wipe out the little subjacent drop of pus, in order to guard against impurity.
1860 J. Ruskin Mod. Painters V. 160 Exclusive of animal decay, we can hardly arrive at a more absolute type of impurity than the mud or slime of a damp, over-trodden path, in the outskirts of a manufacturing town.
2.
a. The state or condition of being morally impure; uncleanness, unchastity; defilement by sin.
ΘΚΠ
society > morality > moral evil > licentiousness > moral or spiritual impurity > [noun]
uncleannesseOE
unpurenessa1425
uncleanliness1509
impurity1548
impureness1557
immundicity1559
sluttery1607
uncleansedness1622
immundity1870
1548 N. Udall et al. tr. Erasmus Paraphr. Newe Test. I. John xiii. 74 Excepte..the affeccions of his mynde be often purged from all impuritie of this worlde.
a1610 J. Healey tr. Theophrastus Characters (1636) 44 Impurity or beastlinesse is not hard to be defined.
a1711 T. Ken Divine Love in Wks. (1838) 292 Let thy love, who art purity itself, create in me a perfect abhorrence of all impurity.
1874 A. H. Sayce Princ. Compar. Philol. viii. 305 Sin and moral impurity are words which he would not understand.
b. With an and plural. That which is or makes impure morally; moral uncleanness or corruption.
ΘΚΠ
society > morality > moral evil > licentiousness > moral or spiritual impurity > [noun] > action or instance of
impurityc1450
c1450 tr. Thomas à Kempis De Imitatione Christi iii. liii. 126 Come, heuenly swetnes, & make fle fro þi visage all maner impurite.
1594 W. Shakespeare Lucrece sig. G1 But no perfection is so absolute, That some impuritie doth not pollute. View more context for this quotation
1639 S. Du Verger tr. J.-P. Camus Admirable Events To Rdr. sig. a ijv Novels..full of impurities, impieties.
1790 J. Beattie tr. Juvenal in Elem. Moral Sci. I. i. ii. 347 Let no visible or audible impurity..enter the apartment of a child.
3.
a. The quality of containing some extraneous or foreign admixture, esp. of an inferior or baser kind; concrete foreign matter which detracts from the purity of any substance.
ΘΚΠ
the world > relative properties > wholeness > mutual relation of parts to whole > condition or state of being mixed or blended > [noun] > admixture or addition as ingredient > adulteration > quality of being adulterated
bastardy1574
impurity1605
unsincerity1661
1605 T. Tymme tr. J. Du Chesne Pract. Chymicall & Hermeticall Physicke i. ix. 37 Saltes haue their corporall impurities.
1704 J. Norris Ess. Ideal World II. iii. 182 The metaphysical..impurity of thought is the..materiality of its object.
1740 G. Smith tr. Laboratory (rev. ed.) ii. 58 Neal the copper..to prevent ashes or other impurities getting to them.
1750 tr. C. Leonardus Mirror of Stones 25 These virtues are varied..by reason of..the purity or impurity of the matter.
1842 E. A. Parnell Elements Chem. Anal. (1845) 19 The hydrochloric acid of commerce is always contaminated with impurities which render it quite unfit for general use as a reagent.
b. An impurity atom; esp. an atom of dopant present at a normal lattice site in an impurity semiconductor.
ΘΚΠ
the world > matter > physics > solid state physics > semiconductivity > [noun] > impurity semiconductor > impurity present in
scatterer1930
impurity1931
acceptor1936
1931 A. H. Wilson in Proc. Royal Soc. A. 134 279 Electrons on a foreign atom [in a semiconductor] do not take part directly in conduction. They must first be transferred by the effect of the lattice vibrations to an atom of the pure substance. In this case the main function of the impurities is to provide electrons for the upper unoccupied energy bands of the crystal, while acting as scatterers is only a secondary function.
1950 W. Shockley Electrons & Holes in Semiconductors i. 12 The conductivity [of the silicon] arises from the presence of arsenic atoms which are termed ‘impurities’, even though added deliberately in the otherwise pure silicon.
1950 W. Shockley Electrons & Holes in Semiconductors i. 14 Impurities with a valence of five are called ‘donor impurities’ because they donate an excess electron to the crystal; those with a valence of three are called ‘acceptor impurities’, since they accept an electron from somewhere else in the crystal.., thus leaving a hole to conduct.
1952 J. S. Koehler in W. Shockley et al. Imperfections in nearly Perfect Crystals vii. 206 The maximum value..of this force occurs when the impurity is two or three atomic distances from the dislocation.
1959 R. A. Smith Semiconductors iii. 45 We must distinguish two types of impurity, substitutional impurities, which replace atoms of the host crystal on their lattice sites, and interstitial impurities which occupy positions in between the lattice sites.
1972 F. J. Bailey Introd. Semiconductor Devices i. 21 By the addition of donor impurities to the silicon, large numbers of free electrons become available as current carriers.
Compounds
Special combinations:
impurity atom n. an atom that differs from the bulk of those present in a substance in being of a different element.
ΘΚΠ
the world > matter > chemistry > atomic chemistry > [noun] > atoms > specific types of atoms
functional group1892
species1895
hetero-atom1900
radio-atom1905
isobar1918
donor1927
impurity atom1939
nuclide1947
strong collider1968
1939 A. H. Wilson Semi-conductors & Metals i. 3 The [electrical] resistance in a metal is caused by the scattering of the electrons by irregularities in the crystal; these irregularities may be due to the presence of impurity atoms and strains or to the temperature motion of the atoms.
1949 Physical Rev. 75 866/1 A substitutional impurity atom from the fifth group has one more valence electron than is required to fill the four valence bonds with neighboring silicon atoms.
1970 W. Bollmann Crystal Defects iv. 37 The elementary point defects are vacancies and interstitial atoms, and also impurity atoms.
1972 F. J. Bailey Introd. Semiconductor Devices i. 21 The doping level refers to the ratio of impurity atoms to silicon atoms. For a transistor this may typically be 1:108, i.e. one impurity atom for every hundred million silicon atoms.
1973 Sci. Amer. Feb. 93/2 If other atoms, which can be referred to as impurity atoms if their concentration is relatively small, are introduced into a helium discharge, the random collisions in the discharge will mix the impurity atoms with the helium atoms.
impurity level n. an energy level in a semiconductor that is due to an impurity atom and generally lies either just above the highest filled (valence) energy band (in the case of an acceptor) or just below the lowest empty (conduction) band (in the case of a donor).
ΘΚΠ
the world > matter > physics > solid state physics > semiconductivity > [noun] > energy band or gap
energy gap1933
impurity level1933
conduction band1939
valence band1956
1933 R. H. Fowler in Proc. Royal Soc. A. 140 507 Semi-conductors with impurity levels full of electrons at low temperatures owe their conductivity to the excitation of electrons to band 1 both from the impurity levels and from band 2, the former predominating at ordinary temperatures.
1964 J. M. Ziman Princ. Theory Solids vi. 169 In a semiconductor there may also be scattering from a neutral impurity—where, for example, an electron has settled in a donor impurity level, or a hole is resident on an acceptor level.
impurity scattering n. scattering of current carriers by impurity atoms in a crystalline solid.
ΘΚΠ
the world > matter > physics > solid state physics > semiconductivity > [noun] > impurity semiconductor > impurity present in > action of
impurity scattering1946
1946 Physical Rev. 69 258/2 (heading) Theory of impurity scattering in semiconductors.
1965 Lindmayer & Wrigley Fund. Semiconductor Devices vii. 259 In crystals used for devices, thermal scattering and impurity scattering dominate the collision processes.
impurity semiconductor n. a semiconductor in which most of the carriers of electric current are electrons and holes from impurity atoms.
ΘΚΠ
the world > matter > physics > solid state physics > semiconductivity > [noun] > impurity semiconductor
impurity semiconductor1946
1946 Trans. Amer. Inst. Electr. Engineers Nov. 713/3 At low temperatures the conductivity of different samples varies by large factors. In this region silicon is said to be an impurity semiconductor.
1950 W. Shockley Electrons & Holes in Semiconductors i. 12 (heading) Impurity semiconductors; donors and acceptors.
This entry has not yet been fully updated (first published 1899; most recently modified version published online June 2022).
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