Environmental Engineering Reference
In-Depth Information
Figure 5.11
Schematic illustration of a metal-deficient compound, M
1
δ
X, predomi-
nantly containing single-charged metal vacancies. The electron holes are assumed to be
localized at M atoms on regular lattice sites, M
•
M
.
stitial cations and 13 cation vacancies (4Fe
•••
i
Fe
), better known as Coch-
Cohen clusters [13]. Examples of systems belonging to p-type semiconductors
are MnO, FeO, CoO, NiO, and Cu
2
O.
Examples of metal-deficient oxides due to interstitial oxygen ion are less. A
typical example is UO
2
δ
. However, the actual situation is much more complex
as has been reported through neutron diffraction studies.
⋅
13V
Figure 5.12
Schematic illustration of a metal-deficient compound, M
1
δ
X, with hypo-
thetical complex metal vacancy defect (Roth cluster).
