Nanocluster immobilization on an oxide surface is fundamentally important for forming nanocluster-assembled layered materials. We fabricated multilayered superatom films made of tantalum-encapsulating Si16 cage nanocluster (Ta@Si16) on a strontium titanate substrate (SrTiO3; STO) by the soft landing of size-selective Ta@Si16. X-ray photoelectron spectroscopy (XPS) revealed that Ta@Si16 survived at the interfacial oxide layer without oxidizing the central Ta atom, and pure Ta@ Si16 layers were formed successively on the modified Ta@Si16/STO interfacial layer. The Ta@Si16 superatoms in the multilayered Ta@Si16 showed high chemical robustness against O2 exposure, although the topmost Ta@Si16 surface layer, including the central Ta atom, completely oxidized in ambient O2 over several days. XPS depth analysis showed that Ta@Si16 oxide formation was limited only at the topmost single layer, revealing that the middle Ta@Si16 layers sandwiched between the top and bottom were protected by the formation of interfacial oxides.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films