Dresden 2020 – scientific programme

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DS: Fachverband Dünne Schichten

DS 12: Thermoelectric and Phase Change Materials

DS 12.3: Talk

Monday, March 16, 2020, 17:00–17:15, CHE 91

Nanoscale characterization of laser-switched Ge₃Sb₂Te₆ with scattering-type Scanning Near-field Optical Microscopy (s-SNOM) and Kelvin Probe Force Microscopy (KPFM) — •Julian Barnett¹, Lukas Wehmeier², Andreas Hessler¹, Konstantin Wirth¹, Susanne Kehr², Lukas Eng², and Thomas Taubner¹ — ¹Institute of Physics (IA), RWTH Aachen — ²Institute of Applied Physics, TU Dresden

Laser-switching of phase-change materials (PCMs) has gathered renewed interest for (re-)writable nanophotonic applications, such as all-optical memory or metasurfaces [1], because their non-volatile transition between two states with distinctly different optical properties allows for local encoding of information. This application-oriented research is based on the development of PCMs with new optical functionalities, requiring a fundamental understanding of physical processes during local switching to optimize speed, cyclability and control over intermediate states.
Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is capable of non-destructive, nanoscale characterization of laser-switched PCM devices [2]. We use s-SNOM in combination with Kelvin Probe Force Microscopy (KPFM) to investigate the local electronic properties of laser-switched Ge₃Sb₂Te₆, where a single measurement clearly shows four distinctive states: as-deposited amorphous, crystallized, melt-quenched reamorphized, and recrystallized.
[1] M. Wuttig et al. (2017), Nat. Photon. 11, 465.
[2] M. Lewin et al. (2015), Appl. Phys. Lett. 107, 151902.