216
5 – Applications
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Figure 83 – emf as a function of the concentration
of added oxide ions (Li 2 O,
ZnO) (from Schenin-King,
1994).
Exercise 5.4 – Calculation of equilibrium constants for defect
formation in Cu 2 O
Copper oxide Cu 2 O is a known p-type semiconductor and has copper vacancies
and holes as its main defects. Analyses of the departure from stoichiometry at
the copper site and measurements of the diffusion tracer
18
O have revealed the
presence of neutral copper vacancies V
#
Cu and singly ionized copper vacancies
V ′ Cu on the one hand, and singly ionized oxygen interstitials O ′ i on the other
hand. Table 46 gives the electrical conductivity of Cu 2 O as a function of the
oxygen partial pressure at 1 000 and 1 100 °C.
Table 46 – Electrical conductivity of Cu 2 O as a function of oxygen
partial pressure at 1 000 and at 1 100 °C (from Peterson & Wiley, 1984).
log P O 2 [bar]
σ 1000 °C [S cm
−1
]
σ 1100 °C [S cm
−1
]
− 1
7.108
12.420
− 1.5
5.754
10.000
− 2
4.677
8.273
− 2.5
3.890
6.844
− 3
3.236
5.662
− 3.5
2.661
4.684
− 4
2.213
3.981
− 4.5
1.884
3.384
− 5
1.641
−