Indium Growth on Reconstructed Si(111), root 3 x root 3 and 4 x 1 In Surfaces

The morphology and growth mechanism of nanostructured metals on semiconducting substrates determine crucially the electronic and physicochemical properties of these adsorption systems. In some cases, these properties are affected by modification of the interfacial geometry, induced by the metal adsorbate on the semiconducting substrate. Thus, in this work we investigate indium growth on the Si(111)3 × 3 and Si(111)4 × 1 surfaces reconstructed by indium. The basic motivation of this study is to reveal how reconstruction of the silicon surface affects the growth mode and electronic properties of the indium overlayer. Therefore, the In/Si interface was mainly studied by Si 2p and In 4d photoemission spectra as well as by valence band measurements using synchrotron radiation. In addition, low-energy electron diffraction, Auger electron spectroscopy, thermal desorption spectroscopy, and electron energy loss spectroscopy were used to reveal the structure and adsorption states of the indium adsorbate on the reconstructed silicon substrates. The results indicate that the initial In-Si surface symmetry affects the growth mechanism of the indium overlayer. In particular, the Stransky-Krastanov mode holds for indium adsorption on the clean Si(111)7 × 7 and Si(111)3×3 In-reconstructed surface. On the other hand, indium develops on the Si(111)4 × 1 In surface according to the Volmer-Weber mechanism. The adsorbate approaches the metallic phase as the coverage approximates the monolayer irrespective of the substrate symmetry.