Surface Plasmon Loss from Reconstructed Si-(111)-7x7 Surfaces Using High Resolution Electron Energy Loss Spectroscopy

For a nonpolar semiconductor such as Si there is no surface optical phonon loss observed from the clean Si-(111)-7x7 surface at room temperature, but a plasmon loss due to free carriers is observed. The plasmon loss peak is very weak so that it is usually not separated from the elastic peak and appears as a broadened quasi-elastic peak in HREELS spectra.