Possible origin of the red luminescence from porous silicon and siliconnanocrystalline

The effect of molecular adsorbates on the luminescence properties of the conventionally prepared porous silicon and silicon nanoparticles was studied. The effect of simple adsorbates (O 2 , H 2 , N 2 ) on the annealed porous Si does not restore red luminescence and gives rise to a weak emission in the violet region. The luminescence reappeared under adsorption of water vapor on the samples. Under the ultra high vacuum conditions from nanoparticles electroluminescence was not observed. The red luminescence of porous Si can be caused by water molecules (together with all possible kinds of impurities) adsorbed in the pores. The porous Si layer can serve as a natural self filter for the emitted light.