Behavior of binary metal adsorbates on Si(111) surface under thermal annealing and ion bombardment using RBS

This paper reviews atomic structures and binding energies of binary Au and Ag atoms adsorbed at the Si(lll) surface which have been studied under thermal annealing and ion bombardment by major use of Rutherford Backscattering Spectroscopy (RBS) and transmission ion channeling with low energy electron diffraction (LEED) and Anger Electron Spectroscopy (AES). On iso-chronal annealing from 200 degrees C to 430 degrees C for 15 min, it is shown by LEED that the Ag/Si(111)-5x1-Au surface shows the root 3x root 3 structure on the initial annealing at 200 degrees C and the Ag/Si(111)-root 3x root 3-Au surface with Ag coverages above 0.6 ML shows the 2 root 3x2 root 3 structure on the initial annealing, which changes into the root(21)x root(21)R(+/-10.89 degrees) structure and furthermore into the root 3x root 3 structure as the temperature rises. The atomic arrangements and binding strengths of Au and Ag at the 2 root 3x2 root 3-(Au,Ag) surface have been determined by ion impact desorption with 5 keV Ar+ ions and transmission ion channeling with 6 MeV Li ions*. The double layered structure and the lattice sites of Au and Ag are proposed and discussed.