Photoluminescence of Inhomogeneous Porous p-type Si

The contribution deals with investigation of photoluminescence (PL) signal recorded on the inhomogeneous porous p-type silicon. PL signal was measured in equidistant points with spacing 0.05 mm. Following parameters were evaluated: 1.) spectral dependence of PL signal and number of identified Gaussian PL peaks; 2.) positions of the peaks; 3.) intensities of peaks; 4.) half-widths (FWHM) of the peaks. PL peaks were localized in vicinity of energies 1.8 and 1.9 eV, respectively. The blue shift of positions of PL maxima was observed and related to increasing PL intensities. The peak 1.8 eV showed increase of FWHM related to increase of blue shift. The peak 1.9 eV showed slight decrease of it. This behaviour is attributed to the increase of the thickness of porous layer and it is related with structural changes. In our opinion, these effects may be related, also, with SiOxHy compounds covering the surface of the structure and their chemical changes induced by applied manufacturing technology of the porous layers.