Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 12: Postersession DS

DS 12.44: Poster

Monday, March 7, 2016, 17:00–19:00, Poster A

Phase transition of pulsed laser deposition-deposited Ge₂Sb₂Te₅ films induced by nano- and femtosecond single laser pulse irradiation — •Xinxing Sun¹, Martin Ehrhardt¹, Andriy Lotnyk¹, Erik Thelander¹, Jürgen W. Gerlach¹, Tomi Smausz², Ulrich Decker¹, and Bernd Rauschenbach^1,3 — ¹Leibniz Institute of Surface Modification, Permoserstr. 15, D-04318, Leipzig, Germany — ²University of Szeged, Dóm tér 9. H-6720 Szeged, Hungary — ³Institute for Experimental Physics II, Leipzig University, Linnéstr.5, D-04103 Leipzig, Germany

Fast phase transformation of Ge₂Sb₂Te₅ (GST) materials is a vital requirement for devices based on phase change materials. In this present work, the crystallization process of pulsed laser deposition (PLD)-deposited GST films irradiated by nano- and femtosecond single pulses at a wavelength of 248 nm with varied laser fluences is compared. Detailed structural information about the phase transformation is elucidated by x-ray diffraction and high resolution transmission electron microscopy (TEM). A high optical reflectivity contrast (25%) between amorphous and completely crystallized GST films was achieved by fs laser single pulse irradiation induced at a fluence between 13 and 16 mJ/cm² and by ns laser single pulse irradiation induced at a fluence between 67 and 130 mJ/cm². Finally, the fluence dependent increase of the reflectivity is discussed in terms of each photon involved into the crystallization process for ns and fs pulses, respectively.