Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 9: Poster I

HL 9.88: Poster

Monday, March 27, 2006, 15:15–17:45, P3

Lattice parameter and hole density of GaMnAs on GaAs(311)A — •Joachim Däubler, Michael Glunk, Wladimir Schoch, Wolfgang Limmer, and Rolf Sauer — Abteilung Halbleiterphysik, Universität Ulm, D-89069 Ulm, Germany

We discuss the structural and electrical properties of GaMnAs layers with Mn concentrations up to 5%, grown on GaAs(311)A substrates by low-temperature molecular-beam epitaxy. High resolution x-ray diffraction studies reveal a higher concentration of As antisites and a weaker linear increase of the relaxed lattice constant with Mn content in the (311)A layers compared to (100) reference layers. The hole densities and Curie temperatures, determined from magnetotransport measurements, are drastically reduced in the (311)A layers. The findings are explained by an enhanced incorporation of Mn atoms on non-substitutional and non-interstitial sites, probably as Mn-Mn or As-Mn complexes, caused by the larger amount of excess As in the (311)A layers.