Onset characteristics of secondary electron emission from Si(100) coadsorbed by Cs and Cl

Abstract

Second derivative energy spectra of secondary electron emission (SE) near the onset have been measured in the coadsorption of Cl and Cs on Si(100). Two SE peaks are observed when Cl atoms are deposited on Cs-covered Si(100), while only one onset peak for the reverse order of deposition of first Cl and second Cs. Both two peaks are ascribed to the SE onsets due to cascade electrons rather than electrons due to the electron density of state above the vacuum level. The appearance of the two SE onsets is quite sensitive to primary electron beam energies, E p. For E p < 150 eV two SE onsets appear, while for E p > 200 eV a single onset appears. This fact suggests that the two SE onsets occur when the secondary electrons are preferentially generated in the selvedge. The surface structure with two SE onsets is still stable even after the Cl atoms are removed by electron stimulated desorption. From a deconvolution analysis of the double peak, we propose a surface structure with Cs rich patches.