Optical properties of nanoparticles prepared by a laser vaporization-controlled condensation technique

Weblike aggregates of Si and ZnO nanocrystals (4 -10 nm diameters) are produced by a laser vaporization-controlled condensation technique. The surface oxidized Si particles show a short-lived blue emission characteristic of the SiO2 coating and a biexponential longer-lived red emission ( with lifetime that ranges from 90 to over 130 mu s at 300 K). The ZnO nanoparticles show emissions that consist of a blue bandgap feature with a subnanosecond lifetime and a green feature with multiexponential lifetime decays.