From Mechanics to Electronics: Influence of ALD Interlayers on the Multiaxial Electro‐Mechanical Behavior of Metal–Oxide Bilayers
Year: 2025
Type: article
Abstract: The applicability of metal‐polymer thin films in flexible electronics and space applications is fundamentally limited by the trade‐off between mechanical and functional performance. This study shows how atomic layer deposited (ALD) amorphous AlO x H y interlayers (0–25 nm) directly control the electro‐mechanical functionality of sputter‐deposited aluminum films on polyimide substrates. Using uni‐ and equi‐biaxial tensile testing with in situ XRD and electrical resistance measurements, it is demonstrated that interlayer thickness determines both deformation mechanisms and electrical strain limits. Adding an ALD layer between the polymer substrate and the metal thin film significantly improves the deformability of the system. While a single ALD cycle enhances ductility, surprisingly a 1 nm AlO x H y interlayer causes early electrical failure. Optimal performance—improved ductility, delayed cracking, and maintained electrical conductivity under large deformation—is achieved at 5–10 nm interlayer thickness. Beyond this range, embrittlement causes early electrical failure through oxide‐initiated cracking. The work establishes quantitative design rules linking the nanoscale interface structure to macroscale electro‐mechanical performance, enabling flexible electronics with tailored mechanical properties and enhanced electrical functionality. These findings provide a direct pathway from fundamental interface engineering to high‐performance flexible devices operating under multi‐axial deformation.
Source: Advanced Functional Materials
Institutions: ETH Zurich, Swiss Federal Laboratories for Materials Science and Technology, National Institute for Materials Science, Austrian Academy of Sciences, Erich Schmid Institute of Materials Science, Montanuniversität Leoben, Centre National de la Recherche Scientifique, Institut Pprime, Université de Poitiers, Université Sorbonne Paris Nord, Laboratoire des Sciences des Procédés et des Matériaux
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
Funders: National Science Foundation, European Commission, Agence Nationale de la Recherche, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Eidgenössische Technische Hochschule Zürich, Amt der Steiermärkischen Landesregierung, Helmholtz-Zentrum Berlin für Materialien und Energie, Japan Society for the Promotion of Science, H2020 Marie Skłodowska-Curie Actions
Awards: G1529220825, Konflikterledigung bei Streitigkeiten aus dem Einzelarbeitsverhältnis., G2645499958, High Cycle Fatigue Cracking of Meso- and Micromechanical Testpieces of Aluminide Intermetallics, with in situ Nanoscale Strain Mapping, G4213164433, G434337789, G4656594441, Mechanics of hybrid nanomaterials: Elucidating plasticity mechanisms at crystalline-metallic/amorphous-ceramic interfaces by nano-mechanical testing, High Cycle Fatigue Cracking of Meso- and Micromechanical Testpieces of Aluminide Intermetallics, with in situ Nanoscale Strain Mapping, Super stretchable novel atomic scale hybrid materials, Poitiers Graduate School on physico-chemical properties of INTerfaces for AeRonautic, Energy and Environment
OpenAlex ID: W4416775206