Electronic properties of W-encapsulated Si cluster film on Si (100) substrates.

We have fabricated thin films composed of W-encapsulated Si clusters (WSi10) on Si substrates and investigated their electronic properties using scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS). An epitaxial layer was observed at the interface with the Si substrate, and an amorphous layer was on top. The bulk plasmon of the WSi10 cluster film was measured and compared with those of crystalline Si (c-Si) and WSi2 films. We found similar plasmon energies in the epitaxial and amorphous layers of the WSi10 cluster film. The plasmon peak of the WSi10 cluster film is shifted to higher energy compared with that of c-Si, which is related to the electron density increase in the valence band. The Si-L23 absorption edge spectra show that the conduction-band density of states in Si was modified by hybridization between Si and W atoms. [ABSTRACT FROM AUTHOR]