46
3 Crystals
diamond
wurtzite
A
B
A
B
C
(a)
(b)
[111]
[00.1]
Fig. 3.17 HRTEM images of a diamond structure (Si, {110} cross section) and b wurtzite structure (GaN, 10.0
azimuth). The ABC and AB stacking is indicated
Table 3.2 Radii of the wavefunctions in the diamond structure, r s and r p are related to s 1 p 3 , r d to s 1 p 2 d 1 and lattice
constant a 0
r s (nm)
r p (nm)
r d (nm)
a 0 (nm)
C
0.121
0.121
0.851
0.3567
Si
0.175
0.213
0.489
0.5431
Ge
0.176
0.214
0.625
0.5646
(a)
(b)
Fig. 3.18 a Unit cell of the zincblende structure with the indication of tetragonal symmetries. The position of the small
yellow (blue) sphere is the tetrahedrally configured unoccupied positions of the A (B) sublattice, denoted with ‘T’ in
part (b). b Line along [111] in the zincblende structure. The positions of the A and B atoms are denoted by red and
green circles as labeled. Other positions are called the bond center (‘BC’), antibonding (‘AB’) relative to A and B atoms
(‘A–AB’, ‘B–AB’), hexagonal (‘H’) and tetrahedral position (‘T’, blue and yellow circles)
We note that α-Sn has little current importance. The diamond structure α–Sn phase is stable below
13.2
◦ C. The addition of Ge inhibits the retransformation to metallic tin up to higher temperatures (e.g.
60
◦ C for 0.75 weight percent Ge). The properties of gray tin are reviewed in [207].
3.4.4 Zincblende Structure
The zincblende (sphalerite,
5 ZnS, space group 216, F ¯
43m) structure (Fig. 3.16b) has a fcc lattice with
a diatomic base. The metal (A) atom is at (0, 0, 0) and the nonmetal (B) atom is at (1/4, 1/4, 1/4)a.
5 Zincblende technically means the material ZnS which occurs in sphalerite (cubic) and wurtzite (hexagonal) phase.
However, in the literature the term ‘zincblende’ for the sphalerite structure is common and used throughout this book.
3 Crystals
diamond
wurtzite
A
B
A
B
C
(a)
(b)
[111]
[00.1]
Fig. 3.17 HRTEM images of a diamond structure (Si, {110} cross section) and b wurtzite structure (GaN, 10.0
azimuth). The ABC and AB stacking is indicated
Table 3.2 Radii of the wavefunctions in the diamond structure, r s and r p are related to s 1 p 3 , r d to s 1 p 2 d 1 and lattice
constant a 0
r s (nm)
r p (nm)
r d (nm)
a 0 (nm)
C
0.121
0.121
0.851
0.3567
Si
0.175
0.213
0.489
0.5431
Ge
0.176
0.214
0.625
0.5646
(a)
(b)
Fig. 3.18 a Unit cell of the zincblende structure with the indication of tetragonal symmetries. The position of the small
yellow (blue) sphere is the tetrahedrally configured unoccupied positions of the A (B) sublattice, denoted with ‘T’ in
part (b). b Line along [111] in the zincblende structure. The positions of the A and B atoms are denoted by red and
green circles as labeled. Other positions are called the bond center (‘BC’), antibonding (‘AB’) relative to A and B atoms
(‘A–AB’, ‘B–AB’), hexagonal (‘H’) and tetrahedral position (‘T’, blue and yellow circles)
We note that α-Sn has little current importance. The diamond structure α–Sn phase is stable below
13.2
◦ C. The addition of Ge inhibits the retransformation to metallic tin up to higher temperatures (e.g.
60
◦ C for 0.75 weight percent Ge). The properties of gray tin are reviewed in [207].
3.4.4 Zincblende Structure
The zincblende (sphalerite,
5 ZnS, space group 216, F ¯
43m) structure (Fig. 3.16b) has a fcc lattice with
a diatomic base. The metal (A) atom is at (0, 0, 0) and the nonmetal (B) atom is at (1/4, 1/4, 1/4)a.
5 Zincblende technically means the material ZnS which occurs in sphalerite (cubic) and wurtzite (hexagonal) phase.
However, in the literature the term ‘zincblende’ for the sphalerite structure is common and used throughout this book.