NaCl- rock salt 2. to the c axis of the AlN epil- The lattice constants for several wurtzite structure semiconductors are … using the first-principles pseudopotential method within the local-d. For wurtzite, there are four atoms per unit cell in contrast to two for zinc-blende. At k 50, the top of the valence band is split by crystal field and spin orbit coupling into the G7vbm(A), G9v(B), and G7v(C) states. structure (ZnO, not included in Table 1.9, is an exception; it is dimorphic with zinc blende and wurtzite structure polymorphs). The wurtzite structure has a hexagonal unit cell with two lattice parameters, a and c, and belongs to the space group P 6 3 mc (No. CdI 2 – cadmium iodide 4. HCP STRUCTURE •ideal ratio c/a of 8/3 1.633 •unit cell is a simple hexagonal lattice with a two-point basis (0,0,0) (2/3,1/3,1/2) a a Plan view •{0002} planes are close packed •ranks in importance with FCC and BCC Bravais lattices 72 Structures derived from hexagonal close packed 1. approxn., and then the band offsets at (111) WZ/ZB interfaces are evaluated for the band-edge states around fundamental gaps. 6 3.. : a six fold screw rotation around the c-axis 3 8 S2Œ ion at of height of unit cell 7 8 Zn2+ ion in midplane (tetrahedrally coordinated by S2Œ) Figure3-25 Wurtzite (ZnS) … An interesting aspect of these compounds is that they can belong to either cubic or in hexagonal symmetry, namely in zincblende(ZB) or in wurtzite(WZ) structure. CdCl 2 – cadmium chloride C. Non close packed structures 1. ZnS – wurtzite 3. The band structures of various semiconductors in both wurtzite (WZ) and zinc-blende (ZB) structures are calcd. Hexagonal wurtzite structure of ZnO is the most stable structure under ambient conditions, which belongs to the space group P6 3mc. They have been widely studied both theoretically and experimentally[1, 2]. The wurtzite crystal structure is referred to by the Strukturbericht designation B4 and the Pearson symbol hP4. ZnS- blende B. Each zinc atom is surrounded by four oxygen atoms, which are located at the corner of a regular tetrahedron and vice versa [18]. NiAs – nickel arsenide 2. A. Structures derived from cubic close packed 1. The corresponding space group is No. Tetrahedrally coordinated binary semiconductors of ANB8−N type having total of 8 valence electrons are compounds of great technological importances. The Brillouin zone integrations were performed by using 6 6 6 -centered k-point grid in all cases. denotes the direction perpendicular ~parallel! CaF 2 – fluorite/Na 2 O- antifluorite 3. diamond 4. 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