Optical degradation experiments were performed on II-VI laser diodes. Micro-focus illumination permitted the degradation of stacking fault-free regions. Degradation was observed only if the excited region was doped with N. Associated with a decrease in quantum-well luminescence, an increase was observed in a deep luminescence signal. The degradation rate decreased under reverse bias. On the basis of density functional calculations, this behaviour could be explained in terms of a displacement of N from a substitutional to an interstitial site. The resultant complex, of a Se vacancy and a N interstitial, was considerably more stable than the N acceptor.

Ab initio Energy Calculation of Nitrogen-Related Defects in ZnSe. S.Gundel, D.Albert, J.Nürnberger, W.Faschinger: Journal of Crystal Growth, 2000, 214-215, 474-7