10. Appendix

684 Appendix C
17 -3
Hall Concentration (10 cm )
3
2
1
T=100K
T=70K
0
0 0.5 1.0 1.5
Pressure (GPa)
Fig. A4.7 Plots of the Hall carrier concentration
in GaAs co-doped with Ge and Te
measured as a function of hydrostatic pressure
at T 77 and 100 K. The open
symbols are the experimental points. The
solid lines are theoretical fits based on a -U
model. Reproduced from Baj et al. [Baj93].
Many other experiments [Mooney88,90; Calleja90, Wolk92, Zeman95] have
helped to firmly establish the properties of the DX center to the point that
it is one of the best understood deep centers in semiconductors.
References for A4.1
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[Bourgoin89] J. C. Bourgoin, Solid State Phenomena, 10, 253 (1989).
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[Dabrowski92] For a discussion on the theory of the do state see, for example, J.
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