Modification of the electronic properties of magic In clusters on Si(111)7 × 7 by different environments

The charge redistribution and the electronic properties of magic In clusters on the Si(111)7 × 7 surface were investigated using scanning tunneling microscopy and spectroscopy. Thereby, special attention was directed to the influence of different environments, such as the orientation of the supporting 7 × 7 half unit cell and the beginning growth of two-dimensional cluster arrays, on the electronic properties of the clusters. It was found that clusters forming in the faulted and the unfaulted half unit cell of the 7 × 7 reconstruction as well as clusters neighboring other clusters exhibit different electronic properties. Although all clusters show a semiconducting behavior, their energy gaps vary. In addition, metal-induced gap states are observed in the tunneling spectra within the energy gap of the clusters due to the metallic states of the surrounding 7 × 7 surface that tail into the energy gap of the clusters. The larger energy gap of clusters neighboring other clusters, a situation that in principle ...