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Proceedings Paper

Ge nanoparticles growth in Ge-doped sol-gel silica by e-beam exposure
Author(s): Norberto Chiodini; Roberto Lorenzi; Alessandro Lauria; Giorgio Spinolo; Alberto Paleari
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Paper Abstract

Silica xerogels doped with Ge(IV), substituting for Si(IV) in the oxide network, are prepared from tetraethylorthosilicate and germanium-tetraethoxide. The sintering process is carried out in reducing atmosphere at 700 - 900° C by reaction with H2. Raman spectroscopy and high resolution transmission electron microscopy (TEM) show that reactions with H2 give rise, in the porous silica network, to uncontrolled islands of crystallites of elemental cubic germanium with average size of 50 nm. Sintering process in reducing H2 atmosphere at temperatures just below the phase separation, at about 610°C, gives materials where Ge atoms are dispersed in the matrix in conditions of incipient clustering. Evidences of segregation of germanium nanocrystals are observed with electron irradiation during TEM analysis. Furthermore, the electron beam induced precipitation leads to the formation of isolated quantum dots-like nanocrystals (5-6 nm in diameter) and with narrower size dispersion. The ranges of suitable temperature and germanium concentration are analysed, as well as the size dispersion of the resulting Ge nanophases.

Paper Details

Date Published: 4 September 2008
PDF: 8 pages
Proc. SPIE 7030, Nanophotonic Materials V, 703003 (4 September 2008); doi: 10.1117/12.793310
Show Author Affiliations
Norberto Chiodini, Univ. of Milano-Bicocca (Italy)
Roberto Lorenzi, Univ. of Milano-Bicocca (Italy)
Alessandro Lauria, Univ. of Milano-Bicocca (Italy)
Giorgio Spinolo, Univ. of Milano-Bicocca (Italy)
Alberto Paleari, Univ. of Milano-Bicocca (Italy)

Published in SPIE Proceedings Vol. 7030:
Nanophotonic Materials V
Zeno Gaburro; Stefano Cabrini; Dmitri Talapin, Editor(s)

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