Correlation between the Porous Silicon Morphology and the Photoluminescence Efficiency

Small‐angle X‐ray scattering is applied to investigate the microstructure and the morphology of three photoluminescent porous silicon samples of the same porosity (80%) but prepared using different electrochemical treatments: (A) as‐prepared, (B) as‐prepared 65% porosity, followed by an oxidation treatment and an oxide dissolution in HF, (C) as‐prepared 65% porosity followed by a HF dissolution. Although the PL spectra are almost similar in energy, there are differences in their intensities: the luminescence intensity of the as‐prepared sample A is a bit greater than the one observed for sample B and much more greater than the one corresponding to sample C. If one assumes the same surface passivation (Si‐H) for the three samples then these differences in luminescence intensity may be due to the different PS morphologies which are evidenced in SAXS curves at low q values.