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Here are the two most important crystal
structures for semiconductors. |
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They are often referred to by the historical names "Zinc
blende" from the German "Zinkblende" = a-ZnS, a rather ubiquitous
mineral. The name "Sphalerite
" also comes form the German: "Sphalerit", which, as was the custom of the time, stems from the Greek
"sphaleros" meaning treacherous or malicious because it is easy to confuse it with other minerals. |
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Wurtzite was and is the name of the b-ZnS
modification - the hexagonal high-temperature variant. The named after the French chemist C. A. Wurtz
(* 1817, 1884), which gives us an idea of how old those names are. |
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Of course we see immediately that what many call Zinc blende
or sphalerite is simply an fcc lattice with two atoms in the base: atom A at (0,0,0,) and atom B at (½,
½, ½). Wurtzite, of course has an hexagonal lattice and ....find it out yourselve!!! ... atoms in the base.
Check the links about lattice and base in general
and hexagonal lattices in particular. |
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Equally of course we notice that we have close
packing, i.e. we simply have a case of ABCABC... stacking of the base, or a ABAB... stacking. |
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From the viewpoint of tetrahedrally coordinated bond angles, it is simply a matter of going
"cis" ( /\ ) or "trans" (
// ). |
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© H. Föll (Semiconductor Technology - Script)