Surface effects on the luminescence properties of colloidal silicon nanocrystals in water

Abstract

Silicon nanocrystals with various size distributions and surface states may yield a wide range of light emission, which makes them a good candidate for color-tuning devices. In this study, emission properties of 2–6 nm sized colloidal silicon nanocrystals (SiNCs) in water are investigated at different excitation wavelengths. Nanosecond pulsed laser ablation of a silicon wafer in water has been carried out to fabricate surface passivated silicon nanocrystals with various size distributions in a simple one-step route. We observed green–red emissions with several peaks in the range of 505–675 nm at different applied excitation wavelengths ranging from 375 to 450 nm. The observed experimental peak emissions are found to be in good agreement with the model of the quantum confinement size effect and radiative centers associated with the Si = O and Si–O–H surface states. This work significantly contributed to understanding the effect of surface states for efficient emission of silicon nanocrystals.