Refractive index change in Al+-ion-implanted silica glass

Abstract

Al+ ions have been implanted in silica glass at an acceleration energy of 200 eV and doses ranging from 1×1013 to 1×1017 ions cm−2. Infrared reflection spectra and ultraviolet, visible, and near-infrared absorption spectra have been measured. It was found that refractive index of silica glass increased by 6%–10% after implantation of 1×1017 Al+ ions cm−2. It was deduced that this refractive index change is caused by the formation of Si—Si homobonds, but not by the decrease in Si—O—-Si bond angle which leads to compaction.

Boson peak, heterogeneity and intermediate-range order in binary SiO2-Al2O3 glasses

“…There are several studies that found evidence for the predominance of this coordination state in low-alumina aluminosilicate glasses. For example, Al ions implanted into silica glass (1 × 10 15 –1 × 10 17 Al + ions cm 2 ) were found to simply substitute on Si-positions 27 . Nuclear magnetic resonance (NMR) and extended X-ray absorption fine structure (EXAFS) have shown that for ≤ 0.4 mol% of Al 2 O 3 , the Al ions are predominantly four-fold coordinated 28,29 .…”

Theory ofAl2O3incorporation inLægsgaard1 2002Phys. Rev. B303270View full textAdd to dashboardCite

“…[3][4][5][6][7] Also Al ions implanted in silica were found to occupy substitutional positions, pushing Si atoms into the interstitial region. [8][9][10][11] However, the state of fully oxidized Al impurities ͑that is, Al 2 O 3 units͒ in a silica network free of other impurities is still an open question. Brower 12,13 found EPR evidence of three-coordinated Al ions in silica fused from natural quartz with low alkali content, but a recent EXAFS 14 study of glass with an Al 2 O 3 concentration of ϳ0.4 mole % ͑compared to the ϳ10-100 ppm weight Al concentration in natural quartz͒ found only evidence of fourcoordinated Al species.…”

Local chemistry of Al and P impurities in silica

“…For Al-implanted silica glass, it has been found 8,11 that the implanted Al atoms are O coordinated for all implantation doses, and that this behavior persists during heat treatments, with no signs of cluster formation. For large implantation doses, Si-Si bonds were seen to form, presumably arising from bonding between the Si atoms that are pushed into the interstitial region.…”

“…A number of experimental investigations have been performed in order to clarify the properties of Al and P impurities in both crystalline and amorphous silica, [1][2][3][4][5][6][7][8][9][10][11] but most of the results obtained are of a qualitative nature. The purpose of the present paper is to complement the experimental information by a theoretical study of the local chemistry governing the behavior of dilute Al or P impurities in a silica environment.…”