Surface Chemistry of Alkyl-Passivated Silicon Nanoparticles Studied by Synchrotron-Radiation Photoelectron Spectroscopy

We have carried out the synchrotron-radiation photoemission studies of n -butyl-passivated Si nanoparticles synthesized by solution routes. After exposure to ambient air, the oxygen contaminants on the present nanoparticle surfaces have been confirmed by Fourier transform infrared and valence-band photoemission spectra, and we have observed an additional feature near the Fermi level in the valence-band photoemission spectrum. This result gives a direct evidence of oxygen-contaminants-induced states in the vicinity of Fermi level that recent theoretical works has predicted. From these results, the detailed surface chemistry of surface-passivated Si nanoparticles is discussed.