Temperature behaviour of luminescence of free-standing porous silicon

The temperature dependence of the luminescence of free-standing samples of porous silicon was studied. Luminescence spectra are composed of three bands at 680+/-20nm, 740+/-20nm and 820+/-20nm, their exact position and intensity differ in spectra taken from the top and bottom sides of the sample. The intensity of all components exhibits different temperature dependence which is responsible for the observed anomalous temperature behaviour of the luminescence spectra of PS. The intensity and the position of the bands are modified by an additional treatment and we suggest that it is caused by the change of the surface states, which substantially influence the luminescence properties of porous silicon.