X-Ray absorption and photoelectron spectroscopic observation of intrazeolitic silicon nanoclusters

The Si-K near-edge absorption spectra and X-ray photoelectron spectra of silicon nanoclusters encapsulated in the pores of zeolite Y are measured; the intrazeolitic Si clusters display a blue shift of the K-edge (0.5 eV) relative to that of bulk Si and a strong room-temperature photoluminescence, which is consistent with the quantum confinement effect; the number of Si in the as-prepared sample is estimated to be 20 atoms per unit cell of zeolite Y from both XPS and Si K NEXAFS analysis.