Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 34: Poster I: III-V Semiconductors
HL 34.24: Poster
Dienstag, 23. März 2010, 18:30–20:30, Poster D2
Optical measurements on Gd doped GaN — •Ole Hitzemann1, Martin Kaiser1, Enno Malguth1,2, Markus R. Wagner1, Jan-H. Schulze1, Axel Hoffmann1, Shalini Gupta2, Tahir Zaidi2, Ian T. Ferguson2, Martin Röver3, Dong-Du Mai3, Jörg Malindretos3, and Angela Rizzi3 — 1Institut für Festkörperphysik, Technische Universität Berlin, Germany — 2School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, USA — 3IV. Physikalisches Institut and VISel, Georg-August Universität Göttingen, Germany
Gd doped GaN has recently gained considerable interest as a potential material for spintronics applications producing a large number of publications. The results, however, are inconsistent: While some authors claim to have achieved ferromagnetic behavior at RT with a high magnetic moment per Gd atom, others did not find any ferromagnetism at all. Optical measurements also showed varying results and there were several contradictory theories describing the role of defects and vacancies for the magnetization. In an attempt to bring clarity to this matter, we examined MOVPE and MBE grown layers of this diluted magnetic semiconductor with Gd concentrations ranging from 1017 cm−3 to 1019 cm−3. p-type and n-type co-doping allowed the investigation of the effect of the position of the Fermi level. We present photoluminescence (PL) spectra of excitonic, DAP and defect luminescence that are related to the incorporation of Gd but also point to other defects and impurities. These results are discussed concerning the ferromagnetic behavior reported for GaN:Gd.