SAXS study of the influence of the porous silicon morphology on the photoluminescence efficiency

Abstract

In this study, we applied small-angle X-ray scattering to investigate the microstructure and the morphology of photoluminescent porous silicon samples prepared by different ways, i.e. highly porous silicon layers produced by electrochemical dissolution of bulk Si in HF, and also lower-porosity layers subsequently oxidized by electrochemical anodisation. The modification which occurs in the scattering pattern after an oxidation treatment indicates the formation of a oxide monolayer at the interface pore-matter. The microstructure obtained after dissolution of this oxide layer in HF is compared with the one of a porous silicon having the same porosity but prepared by electrochemical dissolution. Differences between the scattering profiles appear in the region close to the angular origin which corresponds to large particles (voids or Si skeleton), although the part of the curve corresponding to the pore surface remains similar.