Laser-based method for fabricating monodisperse metallic nanoparticles

An experimental method is presented for fabrication of almost monodisperse metal nanoparticles on substrate surfaces. It relies on substantial narrowi ng of broad size distributions through irradiation with short laser pulses by exploiting the size dependent optical absorption coefficient of the meta l particles. Successive irradiation by applying two laser wavelengths compl etely removes the smallest clusters of the distribution and causes a size r eduction of the largest particles. Finally, only clusters with diameters in a very narrow size interval remain on the surface. By using this method, A g clusters with mean diameters of [d] = 10 nm and size distributions with s tandard deviations of Delta d/[d] = 0.13 have been prepared. (C) 1999 Ameri can Institute of Physics. [S0003-6951(99)01018-9].