Study of Light-Induced Structural Changes Associated with Staebler-Wronski Photo-Degradation in Micro-Crystalline Silicon Thin Films

Abstract

Hydrogenated amorphous silicon based devices lacks behind in their fruitful applications as it suffers from major drawback i.e. light induced degradation or S–W effect. Various theories or literature have been discussed so far, but exact mechanism is still an open challenge in research community. We report on light-induced structural changes in amorphous and micro/nano crystalline silicon by performing light soaking experiments for nearly 8 h. Under vacuum accompanied with the effect of annealing on these films. The electrical, structural and optical properties were analyzed with the use of dark and photo conductivity measurements, Raman spectroscopy, Scanning electron microscopy (SEM) and Photoluminescence studies. Using Raman spectroscopy, we estimated the bond distortion w.r.t degradation percentage in samples. We observed that crystallinity as well as particle size are responsible for increase or decrease in degradation of photoconductivity. Having 72.25 % crystallinity highly stable microcrystalline silicon films showed 1.44 % photo-degradation.