William Angerer - Department of Physics and Astronomy - University ...

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axis perpendicular to the hexagonal plane. The [0001] face of A1 2 0 3 is referred to as
the Q
face, the c-face, or the basal plane.
Structurally, wurzite (see Fig. 5.1) and zincblende crystals are very similar.
VVurzite is formed by stacking planes of Ga and N atom in an ABAB ... sequence
along the (0001) direction, while zincblende is formed from an ABCABC ... sequence
along the (111) direction. The similarity of these structures results in equivalent
nearest neighbors for both the wurzite and zincblende lattices. However, next nearest
neighbors are inequivalent. The actual positions of the Ga and N atoms are determined
by its space group, p6 3 mc. The Ga atoms are located at (0, 0, 0) and (2/3.
1/2, 1/3). while the N atoms are located at (0, 0, u) and (2/3, 1/3, 1/2+u). Table .S.l
displays some of the physical properties of GaN 1. Note, u refers to the displacement
of the Ga sublattice with respect to the N sublattice and has an ideal value of O.375c.
5.2 Band Structure and Electronic Properties of GaN
In this section we discuss spectroscopic structure in the band gap region and we
describe the measured electronic properties of GaN.
lThe point groups are listed in the Schoenflies and international notation respectively. The space
groups are listed in notation of International Tables for X-ray Crystallography [75].
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