Ge nanocrystals in alumina matrix: A structural study

Germanium (Ge) nanocrystals (NCs) embedded in alumina thin films were produced by deposition on silicon (111) substrates using radio-frequency (RF) magnetron sputtering. By changing growth condition and annealing parameters samples with large and small Ge-NCs were produced. The average size of NCs i...

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Bibliographic Details
Published in:Journal of physics. Conference series 2010-02, Vol.209 (1), p.012060
Main Authors: Kashtiban, R J, Pinto, S R C, Bangert, U, Rolo, A G, Chahboun, A, Gomes, M J M, Harvey, A J
Format: Article
Language:English
Subjects:
Aluminum oxide
Germanium
High resolution electron microscopy
Magnetron sputtering
Nanocrystals
Physics
Radio frequency
Silicon substrates
Thin films
X-ray diffraction
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Summary:Germanium (Ge) nanocrystals (NCs) embedded in alumina thin films were produced by deposition on silicon (111) substrates using radio-frequency (RF) magnetron sputtering. By changing growth condition and annealing parameters samples with large and small Ge-NCs were produced. The average size of NCs in the sample with larger NCs was estimated to be 7.2, 30.0 and 7.6 nm, and 5.0, 7.0 and 4.8 nm for the sample with smaller NCs, according to X-ray diffraction (XRD), Raman and high resolution transmission electron microscopy (HRTEM) results, respectively. Both, XRD and Raman peak positions of the larger NCs are shifted to higher angles and larger wave numbers in relation to the Ge bulk values, whereas the Raman peak was red-shifted for the smaller NCs indicating phonon confinement. HRTEM shows twinned structures, which is an indication of relaxation. Strain evaluation of the bigger NCs gave values < 0.5 % which is within the estimated error of the evaluation technique.
ISSN:1742-6596
1742-6588
1742-6596
DOI:10.1088/1742-6596/209/1/012060