Correlation between Optical Properties and Crystallite Size in Porous Silicon

Recently a quantum size effect was proposed to be responsible for the blue shift of optical absorption edge and photoluminescence peak wavelength as well as for the porous silicon (PS) formation itself. In the debate about the mechanism of light emission from PS a correlation between particle size and luminescence peak position would be a key test of the confinement approach. In this letter X-ray diffraction results of as-etched PS samples will be presented that indicate a decrease of particle size and an increase of stress in conjunction with a blueshift of photoluminescence wavelength and absorption edge.