Poster 5

Ignacio Gallardo UT-Physics

Shelled Semiconductor Quantum Dots Generated by Laser Ablation of Microparticles A two step LAM (Laser Ablation of Microparticles) process for ZnS & CdSe core-shell nanoparticle production has been designed. In a first stage, spherical nanoparticles are generated. Before a second ablation cell, they are mixed with microparticles of the second material, (that will form the shell), and the mixture is then ablated. In the second cell, microparticles are ablated as in the first cell but nanoparticles (which have a diameter comparable to the wavelength), on the other hand, do not develop a shockwave. Ablated microparticles condense on top of the nanoparticles, forming the shell. Micrographs show high resolution TEM images. EDS is used to analyse the 4 to 20nm ZnS and CdSe core shell structures. Crystal structure of core and shell is visible in the diffraction patterns. Numerical calculations of the LAM process show the behaviour of nanoparticles at the second ablation cell.