Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 51: Poster IV

HL 51.13: Poster

Thursday, February 28, 2008, 16:30–19:00, Poster D

Raman scattering on a series of phase-change material (GeTe, Sb₂Te₃, Ge₁₅Sb₈₅, and Ge_xSb_yTe_z) — •Judith Hinterberg¹, Reinhard Rückamp¹, Michael Woda², Matthias Wuttig², Gernot Güntherodt¹, and Markus Grüninger³ — ¹2. Physikalisches Institut, RWTH Aachen — ²1. Physikalisches Institut, RWTH Aachen — ³2. Physikalisches Institut, Universität zu Köln

The phase-change material Ge_xSb_yTe_z (GST) are widely used for optical data storage, but also their potential for so-called phase-change (PC)-RAMs is promising. However, their local structure – in particular in the amorphous phase – and the ion displacements across the phase transition are not well understood. In order to reveal the local structure we investigate the phonon spectra of various compounds of the pseudo-binary line from Sb₂Te₃ to GeTe as a function of temperature by means of Raman spectroscopy. In particular, we compare Raman spectra of the amorphous, the metastable, and the stable phases of GST 124, GST 224, GST 214, GST 225, GeTe, Sb₂Te₃, and Ge₁₅Sb₈₅. Near the phase transition, we find a remarkable similarity between GST and Sb₂Te₃. In contrast to recent claims in the literature [1], the ordering process in GST is not only dominated by the Ge atoms.

[1] A.V. Kolobov et al. Nature Mater. 3, 703-708 (2004)