Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster Session I

DS 17.55: Poster

Dienstag, 13. März 2018, 18:15–20:15, Poster B

Structural changes in epitaxial Ge2Sb2Te5 thin films with highly ordered vacancy layers upon ns-laser irradiation — •Mario Behrens, Andriy Lotnyk, Jan Griebel, Jürgen Gerlach, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318, Leipzig, Deutschland

Chalcogenide phase-change materials can be rapidly switched between their amorphous and crystalline phase by being exposed to electrical or optical pulses. Since both phases differ greatly in their reflectivity and conductivity, these materials can be employed for non-volatile optical and electrical data storage based on the phase-change storage mechanism. In this study, ns-laser pulse induced phase transformations of the most prominent chalcogenide phase-change material Ge2Sb2Te5 (GST225), epitaxially grown on Si(111) substrates by pulsed laser deposition, are investigated. X-ray diffraction and aberration-corrected high-resolution scanning transmission electron microscopy of the as-deposited films revealed the formation of cubic GST225 phase with ordered vacancy layers. By applying ns UV-laser pulses the GST225 films were reversibly switched between their crystalline and amorphous state, resulting in a reflectivity contrast of up to 22 %. Within the recrystallization process the amorphous thin films were transformed into a crystalline GST225 phase with disordered vacancies. The influence of laser parameters on the phase changes is discussed.