Zinc Blende and Wurtzite

Here are the two most important crystal structures for semiconductors.
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.
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.
 
zinc blende structure Wurtzite
Zinc blende or sphalerite
or Diamond structure
Wurtzite
or hexagonal structure
Red lines are not showing bonds.
 
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.
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.
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)