title: Ge-Si-O phase separation and Ge nanocrystal growth in Ge:SiO(x)/SiO(2) multilayers--a new dc magnetron approach.
abstract: Ge:SiO(x)/SiO(2)  multilayers are fabricated using a new reactive dc magnetron sputtering approach. The influence of the multilayer stoichiometry on the ternary Ge-Si-O phase separation and the subsequent size-controlled Ge nanocrystal formation is explored by means of x-ray absorption spectroscopy, x-ray diffraction, electron microscopy and Raman spectroscopy. The ternary system Ge-Si-O reveals complete Ge-O phase separation at 400 °C  which does not differ significantly to the binary Ge-O system. Ge nanocrystals of < 5 nm size are generated after subsequent annealing below 700 °C. It is shown that Ge oxides contained in the as-deposited multilayers are reduced by a surrounding unsaturated silica matrix. A stoichiometric regime was found where almost no GeO(2)  is present after annealing. Thus, the Ge nanocrystals become completely embedded in a stoichiometric silica matrix favouring the use for photovoltaic applications.
authors.affiliation: Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400, Dresden, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Zschintzsch
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Sahle
authors.forename: Johannes von
authors.initials: Jv
authors.lastname: Borany
authors.forename: Christian
authors.initials: C
authors.lastname: Sternemann
authors.forename: Arndt
authors.initials: A
authors.lastname: Mücklich
authors.forename: Alexander
authors.initials: A
authors.lastname: Nyrow
authors.forename: Alexander
authors.initials: A
authors.lastname: Schwamberger
authors.forename: Metin
authors.initials: M
authors.lastname: Tolan