Khomenkova L. The role of surface in the excitation processes of porous silicon photoluminescence

Object of investigation - porous silicon. The goal of thesis is the elucidation of the role of silicon crystallite surface in the excitation of red photoluminescence band of porous silicon prepared by anodization technique. Investigation methods - photoluminescent methods (measurements of photoluminescence and photoluminescence excitation spectra), secondary ion mass spectrometry, X-ray photoelectron spectroscopy, infrared absorption, electron paramagnetic resonance, Raman scattering, scanning electron microscopy, atomic force microscopy. It is shown that two ultraviolet and visible excitation bands which correspond to different components of luminescence band are present. It is found that the light emission can be observed in the samples without quantum confinement silicon crystallites. It is shown that surface substances (oxides and silicon-based oxyhydrides) take part in excitation (light absorption) processes. It is found that the main reason of decrease of photoluminescence intensity during therm al treatment is appearance of non-radiative recombination center which are the silicon oxide surface centers. Obtained results may be used for the creation of different type gas sensors as well as biological sensors.