VO2-based thin film shape memory nanoactuators

• Applicants: Professor Dr. Manfred Kohl; Professor Dr.-Ing. Alfred Ludwig
• Subject Area: Synthesis and Properties of Functional Materials ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 278400745

This proposal represents the extension of the project “VO2-Based Thin Film Shape Memory Nanoactuators”. During the previous project, (V-M)O2 (M=3rd metals) thin-film materials libraries have been synthesized by combinatorial co-sputtering with their phase transformation properties and mechanical performances characterized by high-throughput methods. Furthermore, novel nanotechnology processes have been established to obtain VO2-based nanoactuators with dimensions down to 100 nm. A size effect in the electrical resistance change upon the phase transformation of the nanoactuator has been identified. Our research demonstrates the large potential of VO2-based devices for electro-thermo-mechanical as well as thermochromic switching and tuning at the nanoscale, which could meet the urgent need of compact multifunctional solutions in the rapidly evolving field of nanophotonics. The project extension addresses this challenge and goes well beyond the current state-of-the art combining two interlinked parts: Subproject I (RUB) will explore up to quaternary (V-M1-M2)O2 systems in order to improve the mechanical performance of the thin film (e.g., strain and stress change) and to tailor the phase transformation properties. The shape memory oxide ZrO2 will be combined with VO2 to the new system (V-Zr)O2 aiming at an extended stress change and working-temperature range of up to 200 °C. Based on the new material systems, subproject II (KIT) will develop novel nanoactuator designs with enhanced functionality and related fabrication processes for tailoring of out-of-plane curvature and bistable operation. The application of VO2-based films in the field of photonic waveguide switching will be exploited based on the electro-thermo-mechanical and the thermochromic effect as well as alternative electro-optical and all-optical concepts.

• DFG Programme: Research Grants