Octahedral conversion of a-SiO2 host matrix by pulsed ion implantation

• Published in: physica status solidi (b) 2015-10, Vol.252 (10), p.2185-2190
• Main Authors: Zatsepin, D. A., Zatsepin, A. F., Boukhvalov, D. W., Kurmaev, E. Z., Gavrilov, N. V., Skorikov, N. A., von Czarnowski, A., Fitting, H.-J.
• Format: Article
• Language: English
• Subjects: density functional theory; ion implantation; manganese ions; phase transition; quartz; X-ray photoelectron spectroscopy
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201552103

The results of measurements of X‐ray photoelectron spectra (XPS) of a‐SiO2 host material after pulsed implantation with [Mn+] and [Co+, Mn+] ions as well as DFT‐calculations are presented. The low‐energy shift is found in XPS Si 2p and O 1s core‐levels of single [Mn+] and dual [Co+, Mn+] pulsed ion‐implanted a‐SiO2 (E = 30 keV, D = 2×1017 cm−2) with respect to those of untreated a‐SiO2. Similar changes are found in XPS Si 2p and O 1s of stishovite compared to those of quartz. This means that the pulsed ion implantation induces the local high pressure effect that leads to the appearance of SiO6‐structural units in a‐SiO2 host, forming “stishovite‐like” local atomic structure. This process can be described within an electronic bonding transition from the fourfold “quartz‐like” to sixfold “stishovite‐like” high‐pressure phase in the SiO2 host matrix. It is found that such octahedral conversion depends on the fluence and starts with doses higher than D = 3×1016 cm−2.