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DS: Fachverband Dünne Schichten

DS 15: Thermoelectric and Phase Change Materials

DS 15.3: Talk

Thursday, March 21, 2024, 11:00–11:15, A 060

Switching of GeTe-Sb₂Te₃ multilayers by infrared femtosecond laser pulses — •Sonja Cremer¹, Martin Ehrhardt¹, Pierre Lorenz¹, and Andriy Lotnyk^1,2 — ¹Leibniz Institute of Surface Engineering, Leipzig, Germany — ²Laboratory of Infrared Materials and Devices, Ningbo University, China

By phase change material multilayers (MLs) current drawbacks as resistance drift of Ge-Sb-Te thin films for neuromorphic computing may be tackled. This way MLs can help to unleash the full potential of the technologys advantageous characteristics like multilevel cell (MLC) operation. Switching is performed by electric or optical pulses, significantly changing the resistance and reflectivity of the thin film.

Here, we switched PLD grown 30 nm periodic GeTe-Sb₂Te₃-MLs using a 1030 nm laser with 260 fs pulse duration. The laser was part of an optical pump-probe setup to directly monitor reflectivity changes. Successful multiple switching was checked by light microscopy. Follow up SEM and TEM analysis were used to characterize the microstructure evolution. Switching between amorphous and fully crystalline state was found to go along with significant change in reflectivity (~20%). Besides, multilevel crystallization states with nonlinear reflectivity evolution were observed.

Thus, GeTe-Sb₂Te₃-MLs are a potential candidate for MLC operation with a fixed laser wavelength and pulse duration.

We acknowledge financial support by the DFG (No. 445693080) and thank Mrs. A. Mill for FIB preparation.

Keywords: phase change materials; multilayer; optical switching; multilevel storage; microstructure