Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 23: Plasmonics and Nanooptics: Structure, Fabrication and Characterization

O 23.8: Talk

Tuesday, March 17, 2015, 12:15–12:30, MA 043

Material contrasts of layered Phase Change Materials in s-SNOM — •Martin Lewin, Benedikt Hauer, Ann-Katrin U. Michel, and Thomas Taubner — Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany

Phase Change Materials (PCM) show at least two stable states in the solid phase with significantly different physical properties. They can be switched reversibly by optical or electronical means, which enables their use for storage and logical applications [1].

Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is based on an illuminated metal coated tip being scanned over a sample. Due to the local detecting approach, the optical properties of the sample can be analysed wavelength-independently on a nm-scale [2].

Hence, s-SNOM can be used to investigate the switching in nanometre sized phase change devices: We could show that it is possible to distinguish amorphous and crystalline regions of AgInSbTe even below 100 nm of capping layer. Firstly, the material contrasts of a bare 30 nm thick layer of AgInSbTe with and without capping layer are analysed. Secondly, correlative TEM and s-SNOM analyses are performed of a sandwiched amorphous layer with crystalline spots. The found complex material contrasts are explained by theoretical calculations taking into account the layered structure of the sample.

[1] M. Wuttig and N. Yamada, Nature Mater. 6, pp. 824-832 (2007) [2] F. Keilmann and R. Hillenbrand, Phil. Trans. R. Soc. Lond. A 362, pp. 787-805 (2004)