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Achieving facile nucleation of noble metal films through atomic layer deposition (ALD) is extremely challenging. To this end, η⁴‐2,3‐dimethylbutadiene ruthenium⁽⁰⁾tricarbonyl (Ru(DMBD)(CO)₃), a zero‐valent complex, has recently been reported to achieve good nucleation by ALD at relatively low temperatures and mild reaction conditions. The authors study the growth mechanism of this precursor by in situ quartz‐crystal microbalance and quadrupole mass spectrometry during Ru ALD, complemented by ex situ film characterization and kinetic modeling. These studies reveal that Ru(DMBD)(CO)₃produces high‐quality Ru films with excellent nucleation properties. This results in smooth, coalesced films even at low film thicknesses, all important traits for device applications. However, Ru deposition follows a kinetically limited decarbonylation reaction scheme, akin to typical chemical vapor deposition processes, with a strong dependence on both temperature and reaction timescale. The non‐self‐limiting nature of the kinetically driven mechanism presents both challenges for ALD implementation and opportunities for process tuning. By surveying reports of similar precursors, it is suggested that the findings can be generalized to the broader class of zero‐oxidation state carbonyl‐based precursors used in thermal ALD, with insight into the design of effective saturation studies.

Understanding the chemical mechanisms at play in atomic layer deposition (ALD) is critical for effective process development and expansion of ALD into more complex classes of materials. In this work, a mechanistic study of iron oxide deposited by ALD usingtert‐butylferrocene and ozone as reactants is performed. Iron oxide ALD using ozone is a useful model system for mechanistic studies due to the prevalence of ozone‐based ALD processes and the uses of iron oxide in ternary and quaternary metal oxides. Results show that saturation conditions require significantly greater exposures of both reactants than is typically reported in the literature, and growths per cycle of greater than one monolayer of Fe₂O₃per cycle are observed and explained. A growth mechanism is proposed whereby increased ozone exposure results in uptake of superstoichiometric oxygen into the film. X‐ray characterizations reveal the presence of excess oxygen stored near the surface of films deposited with larger ozone exposures and show that increased ozone exposures cause crystalline domain rearrangement and conversion of the film from the γ‐maghemite phase to the α‐hematite phase. The mechanism described here has implications for the wider class of ozone‐based ALD processes, and potential applications of this growth phenomenon are discussed.

The practical implementation of Li metal batteries is hindered by difficulties in controlling the Li metal plating microstructure. While previous atomic layer deposition (ALD) studies have focused on directly coating Li metal with thin films for the passivation of the electrode–electrolyte interface, a different approach is adopted, situating the ALD film beneath Li metal and directly on the copper current collector. A mechanistic explanation for this simple strategy of controlling the Li metal plating microstructure using TiO₂grown on copper foil by ALD is presented. In contrast to previous studies where ALD‐grown layers act as artificial interphases, this TiO₂layer resides at the copper–Li metal interface, acting as a nucleation layer to improve the Li metal plating morphology. Upon lithiation of TiO₂, a Li_xTiO₂complex forms; this alloy provides a lithiophilic surface layer that enables uniform and reversible Li plating. The reversibility of lithium deposition is evident from the champion cell (5 nm TiO₂), which displays an average Coulombic efficiency (CE) of 96% after 150 cycles at a moderate current density of 1 mA cm⁻². This simple approach provides the first account of the mechanism of ALD‐derived Li nucleation control and suggests new possibilities for future ALD‐synthesized nucleation layers.

A synthetic route toward hybrid MoS₂‐based materials that combines the 2D bonding of MoS₂with 3D networking of aliphatic carbon chains is devised, leading to a film with enhanced electrocatalytic activity. The hybrid inorganic–organic thin films are synthesized by combining atomic layer deposition (ALD) with molecular layer deposition (MLD) using the precursors molybdenum hexacarbonyl and 1,2‐ethanedithiol and characterized by in situ Fourier transform infrared spectroscopy, and the resultant material properties are probed by X‐ray photoelectron spectroscopy, Raman spectroscopy, and grazing incidence X‐ray diffraction. The process exhibits a growth rate of 1.3 Å per cycle, with an ALD/MLD temperature window of 155–175 °C. The hybrid films are moderately stable for about a week in ambient conditions, smooth (σ_RMS≈ 5 Å for films 60 Å thick) and uniform, with densities ranging from 2.2–2.5 g cm⁻³. The material is both optically transparent and catalytically active for the hydrogen evolution reaction (HER), with an overpotential (294 mV at −10 mA cm⁻²) superior to that of planar MoS₂. The enhancement in catalytic activity is attributed to the incorporation of organic chains into MoS₂, which induces a morphological change during electrochemical testing that increases surface area and yields high activity HER catalysts without the need for deliberate nanostructuring.