The morphology of nanoporous silicon investigated by time-resolved measurement of changes to the porosity during dissolution

The dissolution rate of porous silicon layers was measured in-situ during etching by HF and NaOH solutions. Cellular models were applied to the structure of the pSi from which the expected rates of change of porosity with time were calculated. Experimental results indicate that the nanostructure of porous silicon may be best modeled as an open-cell foam. This is in contrast to the honeycomb model often used which is not supported by the experimental data.