Electron-energy-loss spectroscopy study of the adsorption of aluminum on the silicon (111) 7 × 7 surface

Electron-energy-loss spectroscopy and low-energy-electron diffraction have been used to study the adsorption of aluminum on the silicon (111) 7 ×{} 7 surface at different substrate temperatures (Tₛ). It is shown that aluminum deposition at a Tₛ of 100-200^∘{}C results in the disappearance of the electronic-surface states of the silicon (111) 7 ×{} 7 surface. New aluminum-induced loss peaks appear at 1.9, 3.2, 4.9, and 7.1 eV. It is further demonstrated that aggregation of aluminum atoms occurs on the silicon surface after the deposition of either two monolayers of aluminum at Tₛ=100-200 ^∘{}C or one monolayer of aluminum at Tₛ=600-700 ^∘{}C.