The intensity of the electron spin resonance signal, associated with dangling bonds in hydrogenated polymorphous Si, was examined after repeated light-soaking and 100C annealing cycles. It was found that the light-induced degradation efficiency decreased with repeated light-soaking (100C) annealing cycles. This result was accounted for in terms of the termination of dangling bonds by mobile H. That is, the termination was enhanced by more mobile H, as a result of the modification of the amorphous network by the light-soaking and annealing cycles. Consequently, the net light-induced defect creation rate was reduced. This contrasted with previous models, in which the decrease in the light-induced degradation efficiency during repeated light-soaking and annealing cycles was attributed to an increase in the amount of H being ineffective for light-induced defect creation.

Light-Induced Defect Creation in Hydrogenated Polymorphous Silicon during Repeated Cycles of Illumination and Annealing. K.Morigaki, K.Takeda, H.Hikita, P.Roca I Cabarrocas: Philosophical Magazine, 2005, 85[29], 3393-407