Scalable, epitaxy-preserving transfer of freestanding perovskite and layered oxide membranes with tunable strain

Abstract

Freestanding single-crystal transition metal oxide membranes enable mechanically flexible devices and heterogeneous integration on diverse substrates, yet scalable transfer without cracking or wrinkling while preserving epitaxy and transport remains challenging. Here, we demonstrate a modified wet release-and-transfer process that transfers large-area epitaxial oxide films (up to 25 mm²) onto silicon, insulating, and flexible substrates using compositionally engineered, water-soluble sacrificial layers and a single polypropylene carbonate (PPC) support layer. The one-layer PPC scaffold enables robust handling and solvent-based removal without a heating step, simplifying processing and limiting thermal exposure. By selecting sacrificial layer chemistry and controlling whether the sacrificial layer remains strained or relaxes, we tune residual strain from compressive to tensile across multiple perovskite and layered oxide membranes, including La_0.8Sr_0.2CoO₃, La_0.7Ca_0.2Ni_0.25Ti_0.75O₃, SrTiO₃, Sr_0.95Ti_0.76Ni_0.05Nb_0.19O₃, and La_1.85Sr_0.15CuO₄, as verified by high-resolution X-ray diffraction and reciprocal space mapping. Systematic analysis of defects formed during release and transfer shows that crack and wrinkle formation is strongly strain-dependent and is further influenced by membrane mechanical compliance and transfer constraints. Finally, temperature-dependent in-plane conductivity measurements demonstrate that defect-minimized membranes retain film-like transport, crack-dominated membranes exhibit pronounced degradation, and wrinkle-dominated membranes show only modest, system-dependent changes. This study establishes a strain-programmable, single-crystal oxide membrane platform that is broadly applicable across multiple perovskite and layered oxide systems and transferable to silicon, insulating substrates, and flexible supports, enabling heterogeneous integration and mechanically compliant oxide electronics.