Berlin 2005 – scientific programme
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HL: Halbleiterphysik
HL 34: Neue Materialien
HL 34.3: Talk
Saturday, March 5, 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.