Berlin 2024 – scientific programme

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DS: Fachverband Dünne Schichten

DS 1: Thin Oxides and Oxide Layers (joint session DS/KFM)

DS 1.5: Talk

Monday, March 18, 2024, 10:45–11:00, A 053

Epitaxy and transfer of freestanding SrTiO₃ membranes — •Jeremy Maltitz, Weaam Ayad, Jens Martin, and Jutta Schwarzkopf — Leibniz-Institut für Kristallzüchtung, Berlin, Germany

Layer transfer of thin films has established a new paradigm of material assembly and design in context of 2D-van-der-Waals crystals. Recently, freestanding oxide perovskite thin films have been achieved by introducing a perovskite-like, water-soluble sacrificial layer (Sr3Al2O6) between substrate and functional film. In combination with layer transfer, this provides a playground for fundamental investigations and technological applications of complex oxides beyond the limitations of classical heteroepitaxy. Requirements are the preparation of epitaxial oxide films with high structural quality of both sacrificial layer and functional oxide film and the controlled detachment from the growth substrate and transfer on another substrate. In this contribution, we will show the influence of the PLD parameters, film thicknesses and composition of the oxide films on the release process and crack formation in freestanding SrTiO3 thin films by using the solid-solution family of (Ba,Ca,Sr)3Al2O6 as sacrificial layer. While cracking of the SrTiO3 films during etching of the sacrificial layer can be largely avoided by the growth of an almost strain-free heterostructure, the transfer process remains challenging. One approach is the use of sub-mm small polymer stamps to transfer deliberately smaller pieces of the functional oxide film on the target substrate.

Keywords: heterostructure; nanomembrane; perovskites; oxides; sacrificial layer