Intrinsic defects in II-VI semiconductors

The properties of vacancies and host interstitials in II-VI semiconductors as determined from magnetic resonance studies are reviewed. A pattern for their electronic structures is shown to follow from a simple one-electron molecular (or atomic) orbital treatment which explains in a natural way the tendency for some to retain full T-d symmetry and for others to distort and become highly localized in low symmetry configurations. It is argued that those that distort are candidates for migration under electronic excitation and involved therefore in II-VI laser degradation. Experiment suggests that the culprits are the interstitials on the two sublattices.