Browsing by Author "Wintrebert-Fouquet, M"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Dielectric properties and photoluminescence of diatomaceous silicas
    (Australian Institute of Physics, 2005-01-31) Jong Wah, JW; Ferris, JM; Wintrebert-Fouquet, M; Butcher, KSA
    Silica shells produced by diatoms have been studied to investigate their potential for applications in electronic and photonic devices due to their dielectric and photoluminescent properties. Dielectric measurements for low (1k-1MHz) and high (∼1GHz) frequencies were performed on processed diatomaceous earth samples and compared with measurements for artificial porous silica samples. Photoluminescence spectra for a sample of freshwater benthic diatoms were obtained and compared with silica spectra. The ratio of the 3.2eV photoluminescence peak compared to a peak at ∼2.20eV is smaller than for pure fused silica, and there is evidence of extra shoulder peak near 2.2eV for diatogenic silica. © 2005 Australian Institute of Physics.
  • Thumbnail Image
    Item
    A luminescence study of porous diatoms
    (European Materials Research Society, 2004-05) Butcher, KSA; Ferris, JM; Phillips, MR; Wintrebert-Fouquet, M; Jong Wah, JW; Jovanovic, N; Vyverman, W; Chepurnov, VA
  • No Thumbnail Available
    Item
    Luminescence study of porous diatoms
    (Elsevier, 2005-12) Butcher, KSA; Ferris, JM; Phillips, MR; Wintrebert-Fouquet, M; Jong Wah, JW; Jovanovic, N; Vyverman, W; Chepurnov, VA
    The cathodoluminescent and photoluminescent properties of the nanoporous silica frustules of various diatom strains and of natural diatom samples are presented. The spectra are observed to be similar to that of pure silica glass and the phenology is therefore believed to also be somewhat similar. A strong U-V-blue luminescence peak is commonly observed as well as a yellow peak at 2.15 eV For the more heavily silicified field-collected freshwater benthic samples, a strong red peak at 1.95 eV is also observed. The 2.15 eV peak is also more strongly evident for the field-collected samples. The U-V-blue peak is related to common silica defect structure but cathodoluminescent microanalysis shows that this emission is highly localized in the diatom samples. © 2005, Elsevier Ltd.
  • Thumbnail Image
    Item
    Variations in the apparent optical band-gap of RPE-CVD grown indium nitride thin films
    (Australian Institute of Physics, 2004-02-05) Butcher, KSA; Wintrebert-Fouquet, M; Chen, PPT; Tansley, TL; Prince, KE
    Indium nitride is a semiconducting material with a band-gap which is in current dispute. Although a ~ 0.75 eV band-gap was announced by some international groups in 2002 [1,2], it has since been shown that all the evidence for a ~ 0.75 eV band-gap is due to deep level defects [3, 4]. Despite this there still appears to be anomolous variations in the apparent bandgap for this material. The Macquarie University Low Temperature Nitride Film Growth Facility has recently grown some very high quality indium nitride thin films by remote plasma enhanced chemical vapour deposition (RPE-CVD). This material shows a variation in the apparent band-gap, as measured by optical absorption techniques, of 1.2 eV to 1.8 eV, dependent on the growth temperature and time. SIMS results measured by the ANSTO SIMS group show that the oxygen content of the films is low and that the variation in the apparent band-gap is not correlated to oxygen content. Other film properties will be described.