Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.117: Poster
Thursday, March 17, 2011, 18:00–21:00, P4
Influence of crystal defects on the magnetic properties of Gd-doped GaN — •Stepan Shvarkov1, Dirk Reuter1, Andreas D. Wieck1, Hans-Werner Becker2, Yvon Cordier3, Jens Herford4, and Achim Trampert4 — 1Ruhr-Universität Bochum, Lehrstuhl für Angewandte Festkörperphysik, Universitätsstr. 150, 44780 Bochum, Germany — 2Ruhr-Universität Bochum, RUBION, Universitätsstr. 150, 44780 Bochum, Germany — 3CNRS-CRHEA, rue Bernard Grégory, 06560 Valbonne, France — 4Paul Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany
Investigations on the role of crystal defects for the magnetic properties of Gd-doped GaN are presented. GaN layers were grown by molecular beam epitaxy (MBE) with Gd atoms incorporated during the growth. Defects were intentionally introduced by performing N+ implantation. The magnetization measured by a superconducting quantum interference device (SQUID) increased after the N+ ions were implanted. In addition, the electrical transport properties of Gd-implanted AlxGa1-xN/GaN high electron mobility transistor (HEMT) structures have been studied. Gd was implanted in the MBE-grown AlxGa1-xN/GaN heterostructures by focused ion beams (FIB). Two sets of the samples were prepared: one set of samples was analyzed as implanted, while the other one was thermally annealed after the Gd implantation so that the number of defects was reduced. Anomalous Hall effect (AHE) was observed for both types of samples. However, AHE measured on the as-implanted samples was found to be much more pronounced than the one of the annealed samples.