The structural resemblance between InSin− and Sin+1 (n = 3–11): Anion photoelectron spectroscopy and density functional calculations

Metal-doped silicon clusters have been extensively studied due to their promising applications in the semiconductor industry and microelectronics. In this study, indium-doped silicon clusters (InSin-/0, n = 3-11) were investigated using anion photoelectron spectroscopy and density functional calculations. It is found that InSin- anions exhibit geometrical and electronic structures resembling their Sin+1 counterparts, with the substitution of one silicon atom by an indium atom leading to exohedral doping and multiple coordination characteristics. The exohedral configuration is attributed to a weak In-Si bond and the limited atomic valence of indium, while the multiple coordination arises from the joint contributions of three orthogonal 5p orbitals of indium atom. Electronic structure similarities between InSin- anions and Sin+1 clusters are confirmed by their identical valence molecular orbitals. The valence p-type orbitals of InSin- primarily contribute to chemical bonding, whereas the valence s-type orbitals predominantly hold electron lone pairs, as demonstrated by the electron localization function and localized molecular orbital analysis. These results provide insights into the structural and electronic properties of indium-doped silicon clusters.