Raman and high-pressure photoluminescence studies on porous silicon

Abstract

We show that there is no correlation between the blue shift of the visible photoluminescence band and red shift of the Raman phonon line in porous silicon, in contrast to the recently reported results. We also report a drastic red shift of the photoluminescence peak position with pressure up to 6 GPa and show that this is much larger than that of the crystalline silicon. These observations cast doubt on the suggested mechanism of quantum size effects in porous silicon.