Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 16: Diffusion and Point Defects I
MM 16.3: Vortrag
Dienstag, 24. März 2009, 12:00–12:15, IFW B
Self-diffusion in Germanium at Low Temperatures — •Erwin Hüger1, Ursula Titze2, Dieter Lott2, Hartmut Bracht3, Dominique Bougeard4, Eugene E. Haller5, and Harald Schmidt1 — 1TU Clausthal, Germany — 2GKSS Forschungszentrum Geesthacht, Germany — 3Universität Münster, Germany — 4TU München, Germany — 5University of California at Berkeley, USA
Self-diffusion in intrinsic single crystalline germanium was investigated between 429 and 596 oC using 70Ge/natGe isotope multilayers. The diffusivities were determined by neutron reflectometry from the decay of the first and third order Bragg peak. At high temperatures the diffusivities are in excellent agreement with literature data obtained by ion beam sputtering techniques, while considerably smaller diffusion lengths between 0.6 and 4.1 nm were measured. At lower temperatures the accessible range of diffusivities could be expanded to values D < 1 × 10−25 m2s−1 which is three orders of magnitude lower than the values measured by sputtering techniques. Taking into account available data on Ge self-diffusion, the temperature dependence is accurately described over nine orders of magnitude by a single Arrhenius equation. An activation enthalpy of diffusion of (3.13± 0.03) eV and a pre-exponential factor of 2.54 ×10−3 m2s−1 for temperatures between 429 and 904 oC are obtained. Single vacancies are considered to prevail self-diffusion in Ge over the whole temperature range.