Photo-degradation in Nanocrystalline Porous Silicon

S.C. Agarwal


We study the metastabilities created by light soaking (LS) in nanocrystalline porous silicon (nc-PSi), prepared by the electrochemical anodization technique. At first sight, these appear similar to the effects of LS observed in hydrogenated amorphous silicon (a-Si:H) prepared by PECVD (Plasma-enhanced chemical vapor deposition) method. In nc-PSi, the ESR (Electron Spin Resonance) and Raman results indicate the presence of a-Si:H. This suggests a-Si:H as a possible cause of photo-degradation in nc-PSi. A careful look, however, reveals the differences. Amongst these is the finding that a polymer coating on nc-PSi is found to stabilize it against LS, but does so only partially for a-Si:H. This and several other experiments seem to indicate that the LS in nc-PSi affects the surface, whereas it is generally regarded to be a bulk effect in a-Si:H. We discuss these and related puzzles and suggest their possible explanations.
Keywords: Light induced degradation, amorphous silicon, nanocrystalline silicon, porous silicon, Staebler Wronski effect, photodegradation

Cite this Article
Agarwal SC. Photo-degradation in Nanocrystalline Porous Silicon. Research & Reviews: Journal of Physics. 2015; 4(1): 22–30p.

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