Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 34: Neue Materialien

HL 34.3: Vortrag

Samstag, 5. März 2005, 15:30–15:45, TU P-N226

Hydrogen in GaMnAs — •C. Bihler¹, H. Huebl¹, C. Noemeier¹, M. S. Brandt¹, S. T. B. Goennenwein², and W. Schoch³ — ¹Walter Schottky Institut, Technische Universität München, 85748 Garchig, Germany — ²Kavli Institute of Nanoscience Delft, Delft University of Technology, 2628 CJ Delft, The Netherlands — ³Abteilung Halbleiterphysik, Universität Ulm, 89081 Ulm, Germany

The hole concentration in the ferromagnetic semiconductor GaMnAs can be adjusted independently from the concentration of Mn by post-growth incorporation of hydrogen. FTIR experiments have shown that Mn-As-H complexes are formed during hydrogenation. To obtain further information on the structural changes induced, we have performed X-ray diffraction experiments. Upon hydrogenation, the unstrained lattice constant of the GaMnAs epilayer increases by Δ a/a=0.6 × 10²⁴ cm³[H]. This increase is markedly lower than the corresponding increase in hydrogenated Si:B which suggests that H is built into GaMnAs on a lattice site such as the antibonding site. In addition, the effective indiffusion of hydrogen is determined via measurements of the ferromagnetic resonance of the thin films where the temperature- and time-dependence of the shift of the collective spin-wave mode upon hydrogenation and anneal is compared to the shifts found upon wet-chemical etching of the films.