Structure and optical properties of silicon nanopowders

Nanopowders obtained in the work by evaporation of silicon ingot with a powerful electron beam with the energy of electrons ∼1.4 MeV in the atmosphere of Ar and N2 is a perspective object as for the fundamental scientific investigations as for the practical application. These materials were investigated by transmission electron microscopy, Raman spectroscopy, photoluminescence spectroscopy, ultrasoft X-ray emission spectroscopy (USXES) and X-ray absorption near-edge structure (XANES). Results of investigations demonstrated that for a mean size of the particles of about 3–4 nm they consist of the ordered nanocrystalline silicon, amorphous silicon and silicon oxide. In this case photoluminescence can be observed in the visible spectral range with a peak at 2.1 eV. USXES spectra show that the particles of the powder consist of the phase with the ordered crystalline structure, amorphous silicon and silicon oxide. According to XANES data, the particles of nanopowders are covered with oxide layer with a thickness that is essentially greater than the natural silicon oxide.