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Title: Multimodal luminescence spectra of ion-implanted silica

Abstract

The main luminescence bands in silica SiO{sub 2} are the red luminescence R (650 nm, 1.9 eV) of the non-bridging oxygen hole center, and the blue band B (460 nm, 2.7 eV) and ultraviolet luminescence UV (290 nm, 4.3 eV), both commonly related to oxygen-deficient centers. In the present work, we will enhance or replace either the first or second constituent of SiO{sub 2}, i.e., silicon or oxygen, isoelectronically by additional implantation of the respective ions. Thus, thermally oxidized SiO{sub 2} layers have been implanted by different ions of the IV group (C, Si, Ge, Sn, Pb) and of the VI group (O, S, Se) with doses up to 5 x 10{sup 16} cm{sup -2}, leading to an atomic dopant fraction of about 4 at % at the half depth of the SiO{sub 2} layers. Very surprisingly, the cathodoluminescence spectra of oxygen-and sulfur-implanted SiO{sub 2} layers show, besides the characteristic bands, a sharp and intensive multimodal structure beginning at the green region at 500 nm up to the near infrared. The energy step differences of the sublevels equal on average 120 meV, and indicate vibration associated electronic states, probably of O{sub 2}{sup -} interstitial molecules.

Authors:
;  [1];  [2]
  1. University of Rostock, Institute of Physics (Germany)
  2. Institute of Ion Beam Physics and Materials Research, Research Center Rossendorf (Germany)
Publication Date:
OSTI Identifier:
21088080
Resource Type:
Journal Article
Resource Relation:
Journal Name: Semiconductors; Journal Volume: 41; Journal Issue: 4; Other Information: DOI: 10.1134/S1063782607040185; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CARBON IONS; CATHODOLUMINESCENCE; EV RANGE 01-10; GERMANIUM IONS; INTERSTITIALS; ION IMPLANTATION; LAYERS; LEAD IONS; MEV RANGE 100-1000; OXYGEN; OXYGEN IONS; SELENIUM IONS; SILICA; SILICON; SILICON IONS; SILICON OXIDES; SPECTRA; SULFUR IONS; TIN IONS; ULTRAVIOLET RADIATION

Citation Formats

Fitting, H.-J., E-mail: hans-joachim.fitting@uni-rostock.de, Salh, Roushdey, and Schmidt, B.. Multimodal luminescence spectra of ion-implanted silica. United States: N. p., 2007. Web. doi:10.1134/S1063782607040185.
Fitting, H.-J., E-mail: hans-joachim.fitting@uni-rostock.de, Salh, Roushdey, & Schmidt, B.. Multimodal luminescence spectra of ion-implanted silica. United States. doi:10.1134/S1063782607040185.
Fitting, H.-J., E-mail: hans-joachim.fitting@uni-rostock.de, Salh, Roushdey, and Schmidt, B.. Sun . "Multimodal luminescence spectra of ion-implanted silica". United States. doi:10.1134/S1063782607040185.
@article{osti_21088080,
title = {Multimodal luminescence spectra of ion-implanted silica},
author = {Fitting, H.-J., E-mail: hans-joachim.fitting@uni-rostock.de and Salh, Roushdey and Schmidt, B.},
abstractNote = {The main luminescence bands in silica SiO{sub 2} are the red luminescence R (650 nm, 1.9 eV) of the non-bridging oxygen hole center, and the blue band B (460 nm, 2.7 eV) and ultraviolet luminescence UV (290 nm, 4.3 eV), both commonly related to oxygen-deficient centers. In the present work, we will enhance or replace either the first or second constituent of SiO{sub 2}, i.e., silicon or oxygen, isoelectronically by additional implantation of the respective ions. Thus, thermally oxidized SiO{sub 2} layers have been implanted by different ions of the IV group (C, Si, Ge, Sn, Pb) and of the VI group (O, S, Se) with doses up to 5 x 10{sup 16} cm{sup -2}, leading to an atomic dopant fraction of about 4 at % at the half depth of the SiO{sub 2} layers. Very surprisingly, the cathodoluminescence spectra of oxygen-and sulfur-implanted SiO{sub 2} layers show, besides the characteristic bands, a sharp and intensive multimodal structure beginning at the green region at 500 nm up to the near infrared. The energy step differences of the sublevels equal on average 120 meV, and indicate vibration associated electronic states, probably of O{sub 2}{sup -} interstitial molecules.},
doi = {10.1134/S1063782607040185},
journal = {Semiconductors},
number = 4,
volume = 41,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • Luminescent measurements are utilized to evaluate the adsorption energy for hydrated uranyl groups on the disperse silica surface. The position of the UO{sub 2}{sup 2+} 0{minus}0 electronic transition and the frequencies of intramolecular vibrations appearing in luminescence spectra were used in that evaluation. The method is based on the dependence of the adsorption bond force constants corresponding to each type of surface sites on the respective perturbation energy of uranyl ions. To calculate the corresponding force constants of adsorption bonds, a vibrational problem is solved. The molecular adsorbate on the silica surface is modeled by means of hypothetical diatomic andmore » triatomic molecules with C{sub {infinity}{nu}} and C{sub 2{nu}} symmetry, in which the UO{sub 2}{sup 2+} ion is predominantly fixed on the silica surface through one and two water molecules, respectively. The perturbations of stretching and deformational vibrations of hypothetical molecules by the presence of the substrate are considered. It has been shown that due to a large value of uranium mass the proposed models can be used for the analysis of vibrational spectra of hydrated uranyl groups adsorbed on the silica surface. A comparison of experimental data with theoretical calculations shows one to suggest that hydrated uranyl groups are attached to the surface by means of two water molecules. The adsorption energy for hydrated uranyl groups physically and chemically adsorbed on the silica surface were evaluated.« less
  • Cobalt and manganese ions are implanted into SiO{sub 2} over a wide range of concentrations. For low concentrations, the Co atoms occupy interstitial locations, coordinated with oxygen, while metallic Co clusters form at higher implantation concentrations. For all concentrations studied here, Mn ions remain in interstitial locations and do not cluster. Using resonant x-ray emission spectroscopy and Anderson impurity model calculations, we determine the strength of the covalent interaction between the interstitial ions and the SiO{sub 2} valence band, finding it comparable to Mn and Co monoxides. Further, we find an increasing reduction in the SiO{sub 2} electronic band gapmore » for increasing implantation concentration, due primarily to the introduction of Mn- and Co-derived conduction band states. We also observe a strong increase in a band of x-ray stimulated luminescence at 2.75‚ÄČeV after implantation, attributed to oxygen deficient centers formed during implantation.« less
  • No abstract prepared.
  • Surface crystallization of a Au$sup +$-ion-implanted lithia-alumina- silica glass was realized. Annealing of a glass sample implanted with 285-keV Au$sup +$ ions at 550$sup 0$C results in the growth of colloidal Au particles of 18 to 35-A radius. The Au particles constitute sites for the precipitation of lithium metasilicate crystals at 550$sup 0$C. Further annealing at 750$sup 0$C allows the growth of quartz and $beta$-spodumene crystals. The crystallized surface obtained after the high-temperature anneal was characterized by a Knoop microhardness number of 626, which is of the order of that obtained for commercial volume-crystallized glass-ceramics of similar composition. (auth)