Tunable, narrow-band light emission from size-selected Si nanoparticles produced by pulsed-laser ablation

Abstract

We have demonstrated narrow-band visible light emission from size selected silicon nanoparticles (np-Si), with a wavelength controlled by size tuning. The np-Si were synthesized by pulsed-laser ablation of a silicon single-crystal target in high-purity He background gas. A postannealing process improved morphology and crystallinity. Using a differential mobility analyzer, nanoparticles were classified with a diameter tunable from 3 to 6 nm. Monodispersed np-Si deposited on substrate exhibited a sharp photoluminescence band. The energy of this band increased from 1.34 to 1.79 eV with decrease in particle size, and narrowed to approximately 0.22 eV full width at half maximum due to highly resolved size-selection and improvement in crystallinity. The results suggest that tunable, narrow-band light emitting np-Si produced by gas phase synthesis have good possibilities for application as optoelectronic devices.