Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 10: Spinelectronics/Spininjection in Heterostructures

MA 10.9: Talk

Monday, March 26, 2007, 17:15–17:30, H23

The effect of flash lamp annealing on Fe implanted ZnO single crystals — •Kay Potzger, Wolfgang Anwand, Helfried Reuther, Shengqiang Zhou, Georg Talut, Gerhard Brauer, Wolfgang Skorupa, Manfred Helm, and Jürgen Fassbender — Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany

Doping of semiconductors with transition metals for the creation of diluted magnetic semiconductors (DMS) recently attracted great attention. For doping of the wide band gap semiconductor ZnO, high temperature processing often leads to diffusion and the formation of unwanted secondary phases. We investigate a combined approach far from thermal equilibrium, i.e. low temperature ion implantation combined with flash lamp annealing. Therefore, ZnO single crystals have been implanted with 3.6 at. % Fe at a temperature of 200 K and flash lamp annealed at a pulse length of 20 ms. For intermediate light power, the implantation induced surface defects could be annealed without creation of secondary phases within the implanted region. At the same annealing temperatures, however, ion beam induced open volume defects start to increase in size. Recrystallization is initiated for the highest light power applied, i.e. the ion beam induced lattice disorder reflected by the minimum channelling yield of Rutherford backscattering spectroscopy decreasing from 76 % to 46 % and the open volume defects are decreased in size. At the same time, the Fe3+ fraction increases at the cost of the Fe2+ states. Weak ferromagnetic properties are induced, that are mainly associated with nanoparticles.