Thin-Film Engineering of Mechanical Fragmentation Properties of Atomic-Layer-Deposited Metal Oxides

Abstract

Mechanical fracture properties were studied for the common atomic-layer-deposited Al2O3, ZnO, TiO2, ZrO2, and Y2O3 thin films, and selected multilayer combinations via uniaxial tensile testing and Weibull statistics. The crack onset strains and interfacial shear strains were studied, and for crack onset strain, TiO2/Al2O3 and ZrO2/Al2O3 bilayer films exhibited the highest values. The films adhered well to the polyimide carrier substrates, as delamination of the films was not observed. For Al2O3 films, higher deposition temperatures resulted in higher crack onset strain and cohesive strain values, which was explained by the temperature dependence of the residual strain. Doping Y2O3 with Al or nanolaminating it with Al2O3 enabled control over the crystal size of Y2O3, and provided us with means for improving the mechanical properties of the Y2O3 films. Tensile fracture toughness and fracture energy are reported for Al2O3 films grown at 135 °C, 155 °C, and 220 °C. We present thin-film engineering via multilayering and residual-strain control in order to tailor the mechanical properties of thin-film systems for applications requiring mechanical stretchability and flexibility.

Molecular layer deposited alucone thin films from long-chain organic precursors: from brittle to ductile mechanical characteristics

“…Please do not adjust margins Please do not adjust margins strain/strength values superior to those for Al 2 O 3 , while Al 2 O 3 has higher cohesive strength owing to its higher elastic modulus. 19,31 Remarkably, the mechanical behavior of our hybrid materials based on the long HD and DD precursors progressively departs from the picture of brittle fracture. After the crack onset strain more cracks are formed with increasing strain, however, the propagation of the crack tips becomes considerably slow, such that it can be captured with the optical microscope (Figures 4, S2 and S3).…”

“…Figure 3 shows the COS (for 100-nm film thickness) and the corresponding R c values (for 50-µm substrate thickness) as a function of the carbon atoms in the organic precursor for our MLD-fabricated alucone films; the reference data for ALDfabricated Al 2 O 3 , and alucone fabricated trough the TMA/1,2ethanediol MLD process are from our previous works. 19,31 The COS values show remarkable progressive increase with the chain length of the organic precursor, such that the value of 9.9±0.2 % is achieved for the film grown using the DD precursor. This value is over an order-of-magnitude higher in comparison to that for the all-inorganic Al 2 O 3 thin film, and is 310 % (relative) higher than the state-of-the-art for the MLDfabricated hybrid materials (the data for the 1,2-ethanediolbased material).…”

MXene/Carbon Nanotube Hybrids: Synthesis, Structures, Properties, and Applications

“…Inspired by the mechanical straining technique (which is a common strategy to create topographic features on the upper layer in a bilayer system where a rigid layer is placed on a soft plate), [123] Zhang et al prepared Ti 3 C 2 T x /CNT hybrids with several out-of-plane features, including concave/convex textures. [122] Specifically, a thin film of Ti 3 C 2 T x /CNT prepared by vacuum filtration was placed on a plasma-treated polystyrene substrate with predrilled holes (the thermally responsive film).…”

Mechanics of Nanoscale ε-Fe2O3/Organic Superlattices toward Flexible Thin-Film Magnets

“…A distinctive feature for the hybrid Fe-TP material is that upon indentation it immediately exhibits plasticity (similar to Al-based MLD hybrid materials). 35,36 Elastic modulus and hardness values were extracted from the unloading slope of the load- Al2O3 and around 150 GPa for ZnO films, 20,28,37 and somewhat lower than 235 GPa for α-Fe2O3 thin films by filtered arc deposition. 38 On the other hand the hardness value is somewhat lower than the 9-13 GPa for ALD Al2O3, 8-13 GPa for ALD ZnO, 20,28,37 and 17 GPa for the α-Fe2O3 thin films by filtered arc deposition.…”