Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster 1

HL 13.7: Poster

Montag, 26. März 2007, 15:00–17:30, Poster A

Effect of hydrogen an silicon co-doping on the magnetic properties of GaGdN grown by MBE — •Martin Roever, Dong-Du Mai, Amilcar Bedoya Pinto, Henning Schuhmann, Tore Niermann, Joerg Malindretos, Michael Seibt, and Angela Rizzi — IV. Physikalisches Institut and Virtual Institute of Spin Electronics (VISel), Georg-August-Universität Göttingen, D-37077 Göttingen, Germany

With the aim of understanding the observed room-temperature giant magnetic moment of highly diluted GaGdN we report on the growth and characterisation of hydrogen and silicon co-doped GaGdN as well as of GaGdN without co-doping. The layers were grown by plasma assisted MBE on MOCVD GaN templates grown on sapphire. Growth was performed at optimised conditions for GaN in the slightly metal rich regime at a substrate temperature of 760 ^∘C. All samples have been doped with Gd and SIMS measurements reveal a Gd concentration between 10¹⁷ cm⁻³ and 10²¹ cm⁻³. Not intentionally co-doped samples show ferromagnetism at room temperature with weak coercivity. Another series of samples, co-doped with activated hydrogen, shows ferromagnetic behaviour at room temperature, too. The coercivity is enhanced, but the overall magnetisation is weaker compared with the non co-doped samples. Because the ferromagnetism in GaGdN is believed to be mediated by electrons the doping with silicon, a n-type dopant in GaN, should increase the magnetisation in this system. Electrical and optical characterisation of all samples are in progress.