RELAXATION MECHANISMS OF ELECTRONIC EXCITATION IN NANOSTRUCTURES OF POROUS SILICON

The temperature dependence of porous silicon (PS) photoluminescence an d the dependence of the contact potential difference (CPD) in the dark after illumination on the photon energy were investigated for as-anod ized PS and for PS oxidized in air for various times after anodization and HF treatment. The effect of the temperature-induced red shift (wi th decreasing temperature) decreases with increasing HF treatment time and is discussed under the assumption of different lifetimes for radi ative and non-radiative recombination. Various photon energy threshold s could be observed by CPD, indicating the role of charge carrier inje ction in the PS properties.