Stabilisation of surface and photoluminescent properties of porous silicon

Using photoluminescence and infrared spectroscopy techniques, we have investigated the influence of surface molecular composition of porous silicon (PS) on the character of its photoluminescence spectra. The main absorption bands of PS in the infrared spectral range are found to be caused by hydride passivation of silicon nanocrystals, adsorption of water molecules and hydroxyl groups during the process of PS formation, as well as by the adsorption of oxygen and carbon due to oxidation of PS. Additional absorption bands found for PS-polyaniline composites are caused by oscillations of molecules that make up the structural polymer chains. The physical and chemical conditions needed for improving photoluminescence stability by means of passivating the PS surface by oxygen and polymer films are substantiated.