Berlin 2012 – wissenschaftliches Programm
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MI: Fachverband Mikrosonden
MI 8: Poster – Microanalysis and microscopy
MI 8.9: Poster
Mittwoch, 28. März 2012, 15:00–17:30, Poster E
Dislocations and cracks in deformed GaN — •Ingmar Ratschinski1, Hartmut S. Leipner1, Jörg Haeberle2, Reinhard Krause-Rehberg2, Ludovic Thilly3, Wolfgang Fränzel2, Gunnar Leibiger4, and Frank Habel4 — 1Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany — 2Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany — 3Département de Physique et Mécanique des Matériaux, CNRS UPR 3346 Université de Poitiers, 86962 Futuroscope Chasseneuil Cedex, France — 4Freiberger Compound Materials GmbH, 09599 Freiberg, Germany
Two inch (0001) GaN single crystals having a thickness of more than 3 mm and a density of in-grown dislocations in the magnitude of 106 cm−2 have been prepared for deformation experiments. GaN specimens of 3.0x3.0x10 mm−3 were fitted into iron cylinders. The samples were compressed more than 9 % at 700 ∘C and 800 ∘C. Furthermore, the as-grown (0001) surface was deformed at room temperature using a Vickers indenter. The samples were indented with loads in the range from 0.02 N to 4.90 N. Dislocations occur at all indentations whereas cracks are formed only at higher loads. The deformed samples were investigated by means of optical microscopy, scanning electron microscopy in secondary electron contrast and cathodoluminescence as well as positron annihilation. The results of compression experiments and indentation tests are compared.