Optical Properties of Quartz Implanted with V Ions

Abstract

V ions were implanted into quartz (single crystals of SiO2) at doses of 3 ×1016–1 ×1017 ions/cm2 at 20 keV. The changes in the optical properties and microstructures were measured while annealing the sample in air at temperatures up to 800 °C. For the as-implanted sample, nanoparticles including V in the metallic state were confirmed to be formed in the implanted layer. The absorption spectrum showed a tendency of monotonic increase toward short wavelengths. When the samples were heated at the temperature range of 450–650 °C in air, a large and narrow absorption peak was observed at approximately 402–418 nm with the tendency to shift toward longer wavelengths as the temperature increased. After heating at 500 °C, the surface of the sample was yellow-green. The micromorphology of the surface was slightly roughened after heating with randomly dispersed microcrystals and concavities. Bleaching of this color occurred when the sample was heated at 550 °C for 30 h or at 700 to 800 °C for 1 h. The surface of the sample heated at 800 °C was found to be flat, and some nanoparticles were still observed in the surface layer. The chemical state of V in the implanted layer of the as-implanted sample was metallic, and after heating at 500 or 800 °C the core line of V 2p3/2 was shifted by about 2.7 eV from that of the metallic state. The binding energy of V 2p3/2 was 515 eV, which corresponds to that of vanadium oxides.