It was recalled that the non-trivial recombination-induced behavior of the familiar low-temperature photoluminescence of the H complex with a Si vacancy (VSi-H) was known to be limited to metastable quenching and/or growth. Non-metastable recombination-induced changes of the VSi-H luminescence in hydrogenated 4H- and 6H-SiC were reported here. It was demonstrated that the phenomenon of recombination-stimulated migration of H at low temperatures may lead to the formation of VSi-H defects, which in certain types of samples was evidenced by a strong nonreversible growth of the corresponding luminescence under above-band-gap excitation. This kind of behavior was rather typical for hydrogenated SiC under optical excitation although it could be masked by the dominating metastable quenching. The concurrent recombination-inducedformation of VSi-H defects explains why the apparent metastable quenching behavior may be very different in different samples. In order to demonstrate that the suggested mechanisms could be responsible for the observed changes in the photoluminescence for a reasonable set of assumptions, a semi-empirical model of the competing quenching and growth kinetics was developed and successfully applied to fit the photoluminescence data.

Metastable and Non-Metastable Recombination-Induced Defect Reactions Involving a Hydrogen Complex with a Silicon Vacancy in SiC. Y.Koshka: Physical Review B, 2004, 69[3], 035205 (8pp)