XAFS Investigation of Nanoparticle Formation in 64Zn+ Ion Implanted and Thermo Oxidized Quartz

Resumo

The silica glass substrates were implanted by ⁶⁴Zn⁺ ions with dose of 5 × 10¹⁶ cm⁻² and energy of 50 keV. During implantation the ion beam current density was less than 0.5 μA/cm² to avoid the substrate magnetically heating. After implantation, the substrates were subjected to isochronous for 1h heat treatment in oxygen atmosphere at temperature range from 400 up to 1000^oC with a step of 100^oC. Zn K-edge EXAFS spectra were measured in fluorescent mode. According to Zn K-edge EXAFS data, Zn in as implanted state and after oxidation at 800^oC is fully oxidized and surrounded by O atoms with coordination number of 4. However, in as implanted state there were disordered orientation of Zn atoms, and ordered tetrahedral coordination occurs only after heat treatment at 800^oC.