Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)

MA 15.105: Poster

Tuesday, March 27, 2007, 15:00–19:00, Poster A

Bulk sensitive HX-PES study of chemically etched Ga_1−xMn_xAs — •Andreas Müller¹, Benjamin Schmid¹, Michael Sing¹, Jan Wenisch², Karl Brunner², Laurens Molenkamp², Wolfgang Drube³, and Ralph Claessen¹ — ¹Experimentelle Physik IV, Universität Würzburg — ²Experimentelle Physik III, Universität Würzburg — ³HASYLAB DESY, Hamburg

Diluted magnetic semiconductors (DMS) have gained particular interest in the last years due to their potential in spintronic applications. One promising candidate for future devices is Ga_1−xMn_xAs (0.04<x<0.07) with Curie temperatures up to 170 K. However, the origin of the ferromagnetic properties is still far from clear.

We investigated the electronic structure of Ga_1−xMn_xAs using hard x-ray photoelectron spectroscopy (HX-PES). For analysing the intrinsic physical properties it is on the one hand essential to remove any surface oxides and adsorbates, since PES is a comparable surface sensitive technique. On the other hand, bulk information can be increased significantly by performing PES in the hard x-ray regime.

Wet chemical etching was used to clean the surface. This technique widely used in the semiconductor industry yields surfaces with controllable roughness and preserved stoichiometry. The samples were etched either in HCl or H₂SO₄ followed by rinsing with deionized water. Information on the depth profile of the composition was gained by measurements under different emission angles at a photon energy of 4.5 keV. Results on all relevant core levels and the valence band depending on the chemical treatment are presented.