Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 33: Ge/Si II
HL 33.7: Vortrag
Dienstag, 27. März 2012, 11:00–11:15, EW 015
Temperature induced phase separation and nanocrystal formation in bulk amorphous SixGeyOz — •Alexander Nyrow1, Christian Sternemann1, Christoph Sahle1, Achim Hohl2, Kolja Mende1, Marco Moretti Sala3, Ralph Wagner4, Alexander Schwamberger1, Inge Brinkmann1, and Metin Tolan1 — 1Fakultät Physik/DELTA, Technische Universität Dortmund, D-44221 Dortmund, Germany — 2Institute for Materials Science, Darmstadt University of Technology, D-64287 Darmstadt, Germany — 3European Synchrotron Radiation Facility, F-38043 Grenoble Cedex, France — 4Fachbereich C -Physik, Bergische Universität Wuppertal, D-42119 Wuppertal, Germany
Since the discovery of the visible luminescence group IV semiconductor nanocrystals (NCs) obtained great attention during recent years. Due to the high efficiency of the luminescence, oxide matrix embedded Ge and Si NCs can be used as high efficient light emitting diodes or as fast and stable non-volatile memory devices. The band structure and thus the optical properties of the NCs depend very strongly on the NC size. Thus, bulk amorphous SixGeyOz can serve as starting material for SiO2 matrix embedded Ge NC production because (i) oxide embedded Ge NCs have a smaller band gap and a higher dielectric constant compared to Si NCs which results in higher charge retention times and (ii) Si is preferentially oxidized so that Ge NC formation can be tuned. In this study, temperature induced phase separation and NC formation have been investigated by x-ray diffraction, x-ray absorption near-edge spectroscopy and x-ray Raman scattering.