ISSN:
1572-9486
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract This review emphasises the information on the binding energies and the identities of electrically impurity and defect centres in II–VI semiconductors which may be obtained from optical spectra. Those shallow centres which may promote useful electrical conductivity are of particular interest. They contribute the richly structured near gap (edge) luminescence, containing weak to moderate phonon coupling and therefore very accessible information about the energy states of the different centres. It is shown that improved material and spectroscopic techniques have yielded considerable information about donors and, particularly shallow to moderately deep acceptors in ZnTe, a key II–VI semiconductor. Persistent impurities such as Li and Cu exert a greater influence on the properties of this semiconductor than formerly supposed. This influence is traced to other II–VI semiconductors, particularly ZnSe. Both the CuZn and PV acceptors appear to be much deeper in ZnSe than in ZnTe due to lattice relaxation, although evidence for a shallow P-related centre, probably a complex, is presented. Finally, some comments are made about the energy states of centres involving native defects in these compounds, particularly the VZn-donor associate centre, responsible for the ‘self-activated’ luminescence.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01596254
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