Photoluminescence of face-centered-cubic structure silicon nanoparticles deposited by pulsed laser ablation

Abstract

Face-centered-cubic (fcc) structure silicon nanoparticles (Si-nps) are synthesized by using nanosecond pulse excimer laser ablation of Si target in Ar ambient. The nonequilibrium environment caused by the plume confined in argon ambient gas is responsible for the formation of fcc Si-nps. Photoluminescence (PL), transmission electron microscopy, and X-ray photoelectron spectroscopy are used to characterize these Si-nps. Broad PL spectrum is obtained with a double-peak at 403 and 503 nm by an exciting laser of 325 nm. After exposure to air for 60 days, air oxidation over time causes a clear blue-shift in green PL peak from 503 to 484 nm and no shift in violet PL peak of 403 nm. The present results indicate that the peak of 503 nm and blue-shift from 503 to 484 nm are attributed to the band-to-band recombination of quantum confinement model, while the violet PL peak of 403 nm is due to the recombination of electron transition from interface states of suboxides.