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| Talk (non-conference) (Other) | FZJ-2025-03810 |
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2025
Abstract: M III.1: Functional Layers - Atomic Layer Deposition(ALD)Vera Barysch (Supervisor: Shicheng Yu)IntroductionAtomic layer deposition (ALD) is a thin-film growth method in which a substrate is first exposedto a gaseous reactant that chemisorbs onto its surface. After purging excess reactant and byproducts,a second gaseous reactant is introduced, reacting with the first layer to form a solid film(Figure 1). By repeating this cycle, the film thickness can be increased with atomic-scale precision.This self-limiting growth mechanism enables precise control over layer thickness and conformality,even on complex 3D surfaces.[1]Figure 3: Schematic depiction of the ALD process. The cycle can be repeated until the desired layer thickness is achieved. [2]The main drawbacks of ALD are its low throughput and relatively high production costs, whichinitially limited its use in functional coatings. However, with the continuing miniaturization ofelectronic devices following Moore’s law, precise nanoscale control has become increasinglyimportant, paving the way for broader ALD adoption. In contrast to chemical vapor deposition(CVD) or sputtering, ALD offers better uniformity and conformality.[1]ApplicationsSince its introduction by Aleskovski in Russia and subsequent commercial development bySuntola et al. in Finland, ALD has been applied in the fabrication of optical devices,semiconductors, and other electronics, as well as in catalysis and anti-corrosion coatings. Inelectrochemical energy systems, notable applications include:- LTO-coated LLZTO solid electrolytes: Li6.45 Al0.05La3Zr1.6Ta0.4O12(LLZTO) was coatedwith nanoscale Li4Ti5O12 (LTO) via TiO2 ALD, reducing grain boundary resistance andimproving Li wettability.[3]- Single-atom Pt catalysts: ALD enables the preparation of Pt single-atom catalysts withhigh catalytic efficiency for the hydrogen evolution reaction.[4]- Gas separation membranes: ALD coatings of Al2O3, ZnO, or TiO2 on polymermembranes modify the microstructure, resulting in tunable CO2 permeation behavior.[5]ALD variantsThermal ALD relies on heat to drive the surface reactions. Plasma-enhanced ALD (PEALD) usesa plasma source to generate reactive species, enabling deposition at lower temperatures and oftenincreasing reaction rates. Radical-enhanced ALD (REALD) similarly introduces highly reactiveradicals, but without the ion bombardment associated with plasma, which can be advantageous forsensitive substrates. More recently, continuous flow ALD has been developed for industrialscalability: in this approach, substrates pass sequentially through dedicated chambers for precursorexposure and purging under constant flow conditions.[1]Questions1. What are the main advantages and limitations of ALD?2. How is ALD relevant to energy research?References[1] Kääriäinen, T., et al., John Wiley & Sons 2013.[2] Seo, J., et al., Nanoscale Adv. 4 2022 1060.[3] Chang, C.-Y., et al., J. Power Sources 652 2025 237593.[4] Cheng, N., et al., Nat. Commun. 7 2016 13638.[5] Niu, X., et al., J. Membr. Sci. 664 2022 121103.
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