Silicon 1s Near Edge X-ray Absorption Fine Structure Spectroscopy of Functionalized Silicon Nanocrystals

Abstract

Silicon 1s Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of silicon nanocrystals have been examined as a function of nanocrystal size (3 – 100 nm), varying surface functionalization (hydrogen or 1-pentyl termination), or embedded in oxide. The NEXAFS spectra are characterized as a function of nanocrystal size and surface functionalization. Clear spectroscopic evidence for long range order is observed Si-NCs that are 5-8 nm in diameter or larger. Energy shifts in the silicon 1s NEXAFS spectra of covalently functionalized silicon nanocrystals with changing size are attributed to surface chemical shifts and not to quantum confinement effects.