Structural studies were made of degraded (Mg,Zn)(S,Se)-based devices. It was found that pre-existing stacking faults turned into non-radiative regions with a high density of dislocation dipoles and dislocation loops. These spread out in <100> directions during current injection. The dislocation dipoles themselves were aligned along both <110> directions on {111} planes; with Burgers vectors of a/2<011>-type that were inclined at an angle of 45 to the (001) junction plane. It was thought that it might be possible to prevent the onset of rapid degradation by eliminating pre-existing defects, and by slowing gradual degradation by reducing the number of point defects.

A.Ishibashi: Journal of Crystal Growth, 1996, 159, 555-65