OPTICAL-SPECTRA OF SILICON NANOSTRUCTURES FROM THE RANDOM-MATRIX MODEL

We apply the method of random matrices to a calculation of the optical properties of porous silicon and silicon nanopowders, analyzing the e ffects of disorder on the visible luminescence properties. The maximum of the luminescence peal; displays a blueshift, which adds up to the effects induced by other mechanisms, such as quantum confinement or su rface passivation, and agrees with the experimental findings, The long -wavelength luminescence edge, instead, is redshifted by the presence of disorder, thus partially compensating for the gap-opening effect in duced by the other mechanisms.