Negative-ion implanter and formation of metal nanoparticles in glass

A negative-ion implanter was developed which brought us precise control of ion energy and dose even for insulators and no particle scattering for powder due to “charge-up free” property. An application of negative-ion implantation for formation of metal nanoparticles in surface layer of glass plate and bead was investigated regarding ion species and optical properties of implanted glasses. Negative ions of copper, silver or gold were implanted into two kinds of glass plates, soda-lime glass (SLG) and silica glass (SOG), at ion energy of 30-35 keV with dose of 1×10¹⁶-1×10¹⁷ ions/cm². Each ion-implanted glass sample showed an optical absorption peculiar to ion species. Each photon energy of their absorption peak well agreed with the each theoretical value of absorption by surface plasmon resonance due to metal nanoparticles with a radius of several nm, which were calculated by using Mie´s scattering theory. As for the nonlinear optical properties, Cu-implanted SLG and SOG showed a large nonlinear optical susceptibility of 1.3×10^-7 and 1.9×10^-7 esu, respectively. As for powders, copper-negative ions were implanted in soda-lime glass beads (an average diameter of 605 μm) at 50 keV with 1 a 10¹⁷ ions/cm² in agitation condition. There was no particle scattering observed during this implantation. Cu-implanted beads also showed an optical absorption due to nanoparticles of copper