Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 14: II-VI semiconductors I

HL 14.5: Vortrag

Dienstag, 28. März 2006, 12:00–12:15, POT 151

Deep defects generated in n-conducting ZnO:TM thin films — •Heidemarie Schmidt, Mariana Diaconu, Holger Hochmuth, Michael Lorenz, Holgerr von Wenckstern, Gisela Biehne, Daniel Spemann, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstrasse 5, D-04103 Leipzig, Germany

The ferromagnetism in highly transparent and intrinsically n-type conducting zinc oxide doped with 3d transition metals (TM), is predicted to be defect mediated. We investigate the generation of deep defects in n-conducting 1 µm thick ZnO:TM films (TM=Co, Mn, Ti) with a nominal TM content of 0.02, 0.20 and 2.00 at% grown by pulsed laser deposition on a-plane sapphire substrates using deep level transient spectroscopy. We find that a defect level is generated, independent of the TM content, located 0.31 eV and 0.27 eV below the conduction band minimum of ZnO:Mn and ZnO:Ti, respectively. Different defect levels are generated in dependence on the Co content in ZnO:Co. The undoped ZnO reference sample reveals the well-known E1, E3 and Eα1 [1] defect level. This work shows that an optimization of defect-related ferromagnetism in n-conducting ZnO:TM thin films will only be possible if the preparation sensitive formation of deep defects is controlled in the same time.

[1] F. D. Auret et al., Appl. Phys. Lett. 80 (2002) 1340 and F. D. Auret et al., phys. stat. sol. (c) 1 (2004) 674.