Defect-related photoluminescence of silicon nanoparticles produced by pulsed ion-beam ablation in vacuum

Visible light emission has been observed from Si nanoparticles produced using an intense pulsed ion-beam evaporation (IBE) technique in vacuum. The as-prepared Si nanoparticles possess good crystallinity without any post-annealing. Room-temperature photoluminescence (PL) spectra for the Si nanoparticles were registered in blue-green range. The average crystal size (around 20 nm) estimated from glancing angle X-ray diffraction (GAXRD) was relatively large, inconsistent with quantum size effect for the light emission. The Si nanoparticles was exposed to O-2 gas at elevated temperature and hydrofluoric acid (HF) vapor at room temperature for examining the PL source, where significant deterioration of PL intensity was found subsequently. Combined with analyses of X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX), the PL is attributable to oxide defects of the samples. (c) 2004 Elsevier B.V. All rights reserved.