CHARACTERIZATION OF ZINC IMPLANTED SILICA - EFFECTS OF THERMAL ANNEALING AND PICOSECOND LASER-RADIATION

Zinc ion implanted silica with controlled thermal treatments and pulse d laser radiation has been investigated. Optical spectra of the as-imp lanted silica at higher doses (>3 X 10(16) ions/cm(2)) and/or the samp les annealed in a reducing atmosphere show both Zn clusters and Zn met al colloid formation. The absorption peak at similar to 5.3 eV is attr ibuted to the surface plasmon absorption of Zn metal colloids in silic a. The oxidized samples with the ion dose greater than or equal to 3x1 0(16) ions/cm(2) show an absorption peak in 4.3-4.7 eV region implying ZnO quantum dot formation. It is expected that the average size of th e ZnO nanoparticles becomes smaller for lower ion dose. Therefore, a b lueshift of the absorption peak with lower ion dose can be attributed to the quantum confinement effects. Pulsed laser radiation at 266 nm w ith energy density of 30 mJ/cm(2) causes a brownish coloration in thes e optically transparent Zn implanted silica substrates. The color form ation is an irreversible process. Therefore, it is believed that new c hemical species may have formed through photochemical reactions. The r esults also show that the coloring process is photon energy dependent. (C) 1998 American Vacuum Society.