LUMINESCENT STRUCTURES OF POROUS SILICON CAPPED BY CONDUCTIVE POLYMERS

Porous silicon (PS) layers capped by conductive polymers (polyaniline (PANI), and polypyrrole (PPY)) demonstrate enhanced photoluminescence (PL) properties with respect to that of bare PS layers. PL measurement s in the temperature range from 4 to 300 K, show that the maximum lumi nescence yield is achieved at 100-150 K, whereas it is strongly quench ed outside this temperature interval. As regards to the spectral line features of PS-polymer composites, they are similar to those of PS fil ms. The PL lines are asymmetrical and may be decomposed into two Gauss ian peaks centred at 1.6 and 1.75 eV. The position of the peaks is not changed with temperature. We assume that the observed PL enhancement is due to interaction of surface silicon atoms with the constituents o f the PANI matrix.