Pulsed laser ablation in pressurized CO2 for nanoparticles fabrication

Pulsed laser ablation in pressurized CO₂ has been applied for fabrication of gold and silver nanoparticles. The gold and silver nanoparticles were successfully generated with allowing the selective generation of clusters. Laser ablation was performed with an excitation wavelength of 532 nm. On the basis of the experimental result, both surface of ablated gold and silver plates and structure of gold and silver nanoparticles were significantly affected by the changes in CO₂ density. As increasing ablation time, plume deposited on the surrounding crater created by the ablation was clearly observed. In FE-SEM image of the generated gold nano-structured particles on silicon wafer, a network structure of smaller gold particles was fabricated. The network structure consists of gold nanoclusters with an average diameter of approximately 30 nm in ensembles of 300-800 nm length. The difference morphology of particles fabricated from silver plate was observed. Based on the results, this new method can also be used to obtain advanced nano-structured materials.