HREELS study of epitaxial Si(111)/WSi2: Correlation with optical properties in the infrared energy range

Abstract Electronic properties of epitaxial WSi 2 layers on top of the Si(111)(7 × 7) surface have been studied by means of high resolution electron energy loss spectroscopy (HREELS) in the loss energy range below 1 eV. A characteristic electronic-type excitation is observed and its origin explained, in the framework of the dielectric theory, through consideration of the IR-optical properties of bulk single crystal WSi 2 . HREELS spectra measured for different WSi 2 overlayer thicknesses allow the identification of contributions from electron gas excitations at the surface and at the interface. AES and LEED analyses have also been carried out for characterization.