Published online by Cambridge University Press: 28 February 2011
Porous Si Alms formed on different p-doped substrates are studied by Raman spectroscopy, photoluminescence, and spectroscopic ellipsometry. Due to a thermal treatment the morphology is changed. A reduction in the number of nanocrystals with diameters below 30Å is found. It is shown that the photoluminescence is caused by the formation of small nanocrystals and that the effect of amorphous Si as a basic mechanism can be ruled out. The strain which must be taken into account for the interpretation of the Raman spectra decreases with increasing heating temperature.