This study explores the role of atomic layer deposition (ALD) as an enabling technique for the defect engineering of catalytically active ultrathin deposits. In particular, we demonstrate the feasibility of tuning the O/Ce ratio in thermal ALD-based cerium oxide layers grown on silicon-based or alumina substrates by using the organometallic precursor tris(N, N'-diisopropyl-2-dimethylamido-guanidinato)cerium(III) ([Ce(dpdmg)(3)]) with H2O, O-2, or O-3 as coreactants. As revealed by in situ X-ray photoelectron spectroscopy (XPS), the Ce3+ concentration, i.e., the concentration of oxygen vacancies, depends strongly on three factors: the type of oxygen source, the chosen substrate, and the film thickness. The fixation of Ce3+ states during the early stages of growth is primarily determined by interface formation and the appearance of silicate and aluminate species, along with changes in morphology and surface-to-volume ratio. For thicker deposits (>5 nm), the intrinsic oxygen vacancies are coreactant-dependent. Furthermore, the chosen oxygen source also influences the morphology of ultrathin deposits, enabling potential surface functionalization with ceria nanoislands of varying composition and size. We point to a likely connection between this chemical and morphological tuning and changes in the ALD reaction pathway. The evolution of different nitrogen and carbon species depends on the oxygen source and the number of ALD cycles, indicating a shift in the ALD reaction mechanism from ligand exchange using H2O to ligand combustion for O-3. The comprehensive investigation of these growth parameters is crucial for tailoring film properties via precise defect engineering.

Zinc oxide (ZnO) is a technologically important wide-bandgap semiconductor used in optoelectronics, sensing, and transparent electronic devices. Implementing ZnO thin films in such devices requires scalable, uniform, and compatible thin-film deposition methods. Atomic layer deposition (ALD) provides precise control over film thickness, composition, and conformality and is established in the semiconductor industry. ALD processes for growing ZnO primarily rely on the pyrophoric diethylzinc (DEZ) precursor. Recently, bis-3-(N,N-dimethylamino)propyl zinc ([Zn(DMP)2]) has emerged as a promising non-pyrophoric alternative, offering improved handling safety and enhanced thermal stability. However, its use has so far been limited to growth on small substrates in proof-of-concept experiments. In this work, a thermal ALD process using [Zn(DMP)2] and H2O as precursors was developed on industrially relevant 200 mm silicon wafers and compared with an established thermal process using DEZ and H2O. The effects of deposition temperature (150-300 degrees C), film thickness, and the underlying substrate material on film growth were systematically investigated. Structural, morphological, chemical, and electrical properties were evaluated using complementary and advanced materials characterization techniques. Across the entire 200 mm wafer area, ZnO films deposited from [Zn(DMP)2] exhibit excellent thickness uniformity and a near-stoichiometric composition comparable to those obtained with DEZ. While slightly higher resistivity and reduced crystallinity are observed at lower deposition temperatures, higher deposition temperatures yield comparable resistivity and an improved c-axis-oriented crystalline texture. Importantly, successful lithographic patterning and electrical characterization of van der Pauw devices confirm compatibility with advanced fabrication workflows. These results demonstrate that [Zn(DMP)2] can compete with DEZ in terms of film quality on large-area wafers and is safer to handle, providing a significant overall advantage.

Hafnium disulfide (HfS2) is expected to surpass MoS2 and WS2 as a two-dimensional (2D) semiconductor, with the added advantage that its native oxide, HfO2, is a widely used high-k dielectric. Unlike MoS2 and WS2, which are generally synthesized by metal-organic chemical vapor deposition (MOCVD) for semiconductor applications, HfS2 has not yet been grown by this method, probably due to a lack of suitable precursors for depositing thin, uniform, and stoichiometric films. Here, we introduce two nitrogen-coordinated hafnium precursors, [Hf(TMSAEDMA)(NMe2)3] 1 and [Hf(TMSAEDMA)(NEtMe)3] 2, derived from the functionalized ligand system N-trimethylsilylamino-ethane-N',N'-dimethylamine (TMSAEDMA). Both complexes exhibit adequate volatility and high reactivity toward elemental sulfur, enabling MOCVD under moderate, H2S-free conditions. Using precursor 1, crystalline HfS2 was deposited, confirmed by structural and compositional analyses. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed rapid surface oxidation to HfO2 and HfOxSy, naturally forming heterostructures relevant for transistor applications. For electrical characterization, HfS2 films were directly deposited on interdigitated electrode (IDE) structures. Their conductivity was evaluated both with the native oxide present and after capping with a thin ZnS layer, with both configurations preserving the conductivity. This work establishes the first MOCVD method for high-quality HfS2, identifies 1 as a versatile precursor for chalcogenide growth, and provides detailed insights into oxidation pathways, highlighting the material's potential for next-generation semiconductor devices.

The application of a liquid and volatile Ru precursor ([eta 5-C5H5Ru(CO)2(CH2)3N(CH3)2] or dicarbonyl(eta 5-cyclopentadienyl)(3-(dimethylamino)propyl)ruthenium, trade name HeRu31) in an atomic layer deposition (ALD) process yielded high-purity and conductive Ru metal thin films. The films were deposited at temperatures from 200-300 degrees C on Si substrates, exhibiting self-limiting, linear growth behavior with a growth per cycle (GPC) of 1.1 & Aring; at a deposition temperature (T dep) of 280 degrees C. Comprehensive characterization of Ru thin films validates the growth of closed, nanocrystalline Ru films with resistivities in the range of 24-29 mu Omega cm. These unprecedented findings offer further insights into the impact of the Ru precursor, paving the way to explore Ru films for microelectronic applications.

The exploration of Nd and Eu precursors bearing the (form-)amidinate ligand for atomic layer deposition (ALD) with water resulted in crystalline Nd2O3 and Eu2O3 thin films on Si substrates at low temperatures. Eu2O3 films exhibit strong photoluminescence with well-defined 5D0 -> 7F j transitions that evolve from surface-dominated to bulk-like emission as thickness increases, approaching the optical quality of single crystals. In contrast, Nd2O3 shows temperature-dependent visible emission from defect states rather than f-f transitions, while controlled nitrogen incorporation at 350 degrees C induces room-temperature luminescence through defect engineering. Leveraging the high reactivity of the Nd and Eu precursors, which was predicted and confirmed by density functional theory (DFT) studies, atomic and molecular layer deposition (ALD/MLD) experiments using -OH and -NH2 containing organic coreactants were performed. Using terephthalic acid (TPA) as a coreactant resulted in high growth per cycle (GPC) values (3.1 & Aring; for Nd-TPA and 3.3 & Aring; for Eu-TPA). Additionally, adenine, guanine, and melamine were successfully introduced as organic linkers, along with rare-earth (RE) precursors. Besides reporting promising water-assisted ALD processes for Nd2O3 and Eu2O3 thin films, this study broadens the range of RE-organic materials available and highlights the importance of designing targeted precursors.

Zinc oxide (ZnO) is a technologically important wide-bandgap semiconductor used in optoelectronics, sensing, and transparent electronic devices. Implementing ZnO thin films in such devices requires scalable, uniform, and compatible thin-film deposition methods. Atomic layer deposition (ALD) provides precise control over film thickness, composition, and conformality, and is a well-adapted process in the semiconductor industry. ALD processes for growing ZnO primarily rely on the pyrophoric diethylzinc (DEZ) precursor. Recently, Bis-3-(N,N-dimethylamino)propyl zinc ([Zn(DMP) 2 ]) has emerged as a promising non-pyrophoric alternative, providing improved handling safety and enhanced thermal stability. However, its use has so far been limited to growth on small substrates in proof-of-concept experiments. In this work, a thermal ALD process using [Zn(DMP) 2 ] with H 2 O as precursors was developed on industrially-relevant 200 mm silicon wafers and compared to an established thermal process with DEZ and H 2 O. The effects of deposition temperature (150-300 °C), film thickness, and the underlying substrate material on film growth were systematically investigated. Structural, morphological, chemical, and electrical properties were evaluated using complementary and advanced materials characterization techniques. Across the entire 200 mm wafer area, ZnO films deposited from [Zn(DMP) 2 ] exhibit excellent thickness uniformity and a nearstoichiometric composition comparable to those obtained with DEZ. While slightly higher resistivity and reduced crystallinity are seen at lower deposition temperatures, higher deposition temperatures yield comparable resistivity and an improved c-axis oriented crystalline texture. Importantly, successful lithographic patterning and electrical characterization of van der Pauw devices confirm compatibility with advanced fabrication workflows. These results demonstrate that [Zn(DMP) 2 ] can compete with DEZ in film quality on large-area wafers and is safer to handle, which is a significant advantage overall.

The large-scale deposition and integration of 2D materials on 200 mm wafers for emerging microelectronic applications are highly challenging. Throughout the processing, significant issues in controlling material growth and patterning must be addressed. Therefore, this study introduces a new approach for bottom-up growth and subsequent patterning of ultrathin 2D WS2 layers on 200 mm wafers. To achieve this, atomic layer deposition (ALD) was used to grow WS2 thin films directly on 200 mm wafers, which were then patterned by photolithography and ion-beam etching. To prevent degradation and delamination of the WS2 layer during patterning, an in situ Al2O3 ALD capping layer is employed. Even after treatment in boiling de-ionized water, which porosifies the Al2O3 as needed for sensing applications, the WS2 and underlying features remain intact. To investigate the effects of patterning and capping processes in detail, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were used. The detailed analysis shows that the proposed strategies enable patterning of WS2 layers on 200 mm wafers using Al2O3 capping layers. Electrical measurements of the WS2 patterned on interdigitated electrodes show a linear current response and an average resistance of 0.4 +/- 0.26 M Omega across the 200 mm wafer. Overall, our findings indicate a promising step toward the scalable integration of WS2 into various micro- and nanosystems, especially sensors, and support future scaling of these processes.

ABSTRACT We investigated the functionalization of pristine and post‐deposition‐annealed atomic layer deposition (ALD)‐grown MoS 2 films on silicon wafers with the polyoxometalate (POM) ( n Bu 4 N) 3 [HV 12 O 32 Cl(DyPc)] (referred to as V 12 ‐ DyPc ) and its impact on the optical and electronic properties of 2D semiconductor layers. Thin‐film analysis confirms the formation of high‐quality, polycrystalline MoS 2 after annealing. The deposition of V 12 ‐ DyPc induces a concentration‐dependent reduction in A exciton emission and the emergence of negatively charged trion (A – ) photoluminescence (PL), evidencing systematic charge transfer. Studies on thinner MoS 2 layers grown by metal‐organic chemical vapor deposition (MOCVD) corroborate this effect. Short‐range surface ordering of POMs is detected on pristine, amorphous MoS 2 . Notably, V 12 ‐ DyPc exhibits identical multilevel switching behavior on both amorphous and polycrystalline, annealed MoS 2 . On MoS 2 , V 12 ‐ DyPc shows a significantly reduced lateral electronic density distribution (3 nm compared to 7 nm on highly oriented pyrolytic graphite (HOPG)) and a more positive first reduction potential (3.1 V vs. 2.1 V, respectively). These changes are due to the substantially increased surface roughness of MoS 2 relative to the atomically flat HOPG substrate, and to the impact of a modified chemical environment on MoS 2 . Density functional theory (DFT) and molecular mechanics simulations reveal face‐on bonding geometries, altered redox energetics, and substrate‐dependent shifts in electronic states.

Abstract The most conventional atomic layer processing method, atomic layer deposition (ALD), delivers ultrathin blanket coatings with sub-nanometer thickness precision. Lateral confinement underpins the direct atomic layer processing (DALP®) family of deposition techniques. ALD chemistry applied to DALP® is a 3D printing method called atomic-layer additive manufacturing (ALAM). Here, we demonstrate the applicability of ALAM to the additive buildup of the crucial ZnS / Sb2S3 / V2O5 semiconductor stack which constitutes an functional inorganic solar cell. To this goal, ALAM processes are first optimized and evaluated for the individual materials vanadium(V) oxide, zinc sulfide, and antimony(III) sulfide. We establish the layer-by-layer growth mode controlled by self-limiting surface chemistry and characterize the materials’ structure and the smooth surface morphology of ALAM-coated areas. Finally, all three materials are 3D-printed in ALAM mode in combination with electrodes and the electron acceptor titania (TiO2) to form functional solar cells with a 120 nm thick Sb2S3 absorber layer. This novel fabrication of solar cells highlights the advantages of using direct patterning in the prototyping and optimization of photovoltaics in research and development.

This work presents the first report of thermal atomic layer deposition (ALD) of NiOx using two nickel precursors - Alanis (TM) and [Ni(ipki)2] - in combination with two different oxygen sources (H2O and O3), over a temperature range of 75-250 degrees C. The Alanis/O3 composition exhibited one of the highest growth rates per cycle (1.1-1.4 & Aring;) and a broad ALD window between 100 and 200 degrees C. In contrast, the Alanis/H2O and [Ni(ipki)2]/O3 combinations yielded lower growth rates of 0.74 & Aring; at 150 degrees C and 0.40 & Aring; at 250 degrees C, respectively. Comprehensive structural, morphological, optical, and chemical characterisation revealed that the choice of precursor combination and the reaction temperature significantly impact the film composition, thereby strongly influencing its suitability for various applications. Notably, those parameters closely determined the photoelectrochemical performance and the stability of the Si/NiOx-based photoanode towards the oxygen evolution reaction (OER). Photoelectrodes fabricated with Alanis/O3 at 200 degrees C demonstrate stability exceeding 24 hours and exhibit a remarkable OER onset potential of 1.15 V vs. RHE for a photocurrent density of 1 mA cm-2.

Abstract The application of a liquid and volatile Ru precursor ([η5-C5H5Ru(CO)2(CH2)3N(CH3)2] or dicarbonyl(η5-cyclopentadienyl)(3-(dimethylamino)propyl)ruthenium, trade name HeRu31) in an atomic layer deposition (ALD) process yielded high-purity and conductive Ru metal thin films. The films were deposited at temperatures from 200–300 °C on Si substrates, exhibiting self-limiting, linear growth behavior with a growth per cycle (GPC) of 1.1 Å at a deposition temperature (Tdep) of 280 °C. Comprehensive characterization of Ru thin films validates the growth of closed, nanocrystalline Ru films with resistivities in the range of 24–29 μΩ cm. These unprecedented findings offer further insights into the impact of the Ru precursor, paving the way to explore Ru films for microelectronic applications.

This study explores zinc-functionalized chitosan (CS) for engineering bio-multifunctional interfaces via three atomic-scale techniques: vapor phase metalation (VPM), multiple pulsed vapor phase infiltration (MPI), and O2 plasma-enhanced atomic layer deposition (PEALD). X-ray photoelectron spectroscopy (XPS) analysis and scanning electron microscopy (SEM) with integrated energy-dispersive X-ray (EDX) elemental mapping confirmed homogeneous Zn distribution in all regimes, while AFM revealed a topographical transition from planarization in VPM (Rq = 5.6 nm) to high-surface-area nucleation in MPI (Rq = 123.9 nm). X-ray diffraction (XRD) analysis demonstrated structural reconfiguration, with VPM reducing the hydrated phase crystallite size (7.4 to 4.6 nm) and MPI achieving the finest nanocrystallinity (1.83 nm). Notably, PEALD-modified interfaces exhibited the highest interfacial energy (0.102 J/m2) and enhanced swelling. Physicochemical characterization showed the functionalization method dictates semiconductor properties, while biological assays revealed C2C12 cell proliferation comparable to the control, along with tailored antiseptic activity against E. coli and H. pylori. Significantly, in vivo subcutaneous implantation revealed that CS-ZnO PEALD scaffolds act as immunomodulatory interfaces, promoting active angiogenesis and a balanced immune response with stable anti-inflammatory IL-10 levels and near-basal pro-inflammatory expression (IL-6 = 0.5 pg/mL). These findings highlight the versatility of ALD-based processes for next-generation intelligent medical implants and bio-integrated electronics.

New Zr(iv) and Hf(iv) complexes were synthesized and applied as molecular precursors for chemical vapor deposition (CVD) of zirconium-, hafnium-, and mixed hafnium-zirconium-oxide (HZO) coatings. Reaction of tetrakis(diethylamido)metal(iv) complexes (M = Zr, Hf) with the fluorinated beta-ketoenamine ligand (Z)-4-(tert-butylamino)-1,1,1-trifluorobut-3-en-2-one (H-TFB-tBuA) and tert-butyl alcohol produced new heteroleptic [M(TFB-tBuA)2(OtBu)2] zirconium (Zr-1, M = Zr) and hafnium (Hf-1, M = Hf) complexes. Both compounds possess excellent thermal stability up to 250 degrees C and exhibit volatility suitable for chemical vapor deposition of ZrO2 and HfO2 thin films in a low-pressure (10-2 mbar) chemical vapor deposition reactor. The vapor pressure and thermal stabilities of both Zr-1 and Hf-1 are compatible for the co-deposition of individual metal oxides, enabling direct synthesis of phase-pure HZO films with a tunable Zr : Hf ratio. The co-evaporation without preferential decomposition of either precursor was attributed to the matched decomposition profiles of Zr-1 and Hf-1, enabling the single-step deposition of mixed-metal HZO films.

Ru-based thin films are essential for electronics and catalysis. Their growth through atomic layer deposition (ALD) depends on precursors that balance reactivity, volatility, and thermal stability. We present the first Ru dicarbonyl bisamidate complexes as a new and promising class of ALD precursors for Ru-based materials. Modifying the substitution pattern of the amidate ligands yielded [Ru(CO)2(N-sBuiPrAD)2], as a volatile liquid precursor with excellent thermal properties. First principles simulations predict favorable interactions with common ALD co-reactants, indicating its potential for thin film deposition.

Atomic layer deposition (ALD) of zinc oxide (ZnO) has been widely researched using diethyl zinc (DEZ)-based methods. The significant importance of thin films of ZnO as transparent conductive oxides (TCO) in optoelectronic devices and photovoltaics warrants examining alternative Zn precursors for ZnO ALD as potential replacements for the pyrophoric DEZ. In this study, we investigated three alternative Zn precursors: Zn(EEKI)2, Zn(DMP)2, ZnEt(HMDS), in the process development for high-quality ZnO thin films and compared them to DEZ. The ALD processes were studied using in situ spectroscopic ellipsometry. The properties of the ALD ZnO films were characterized using ex situ X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry and nuclear reaction analysis (RBS/NRA), X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), and ultraviolet-visible (UV/Vis) spectrophotometry. These measurements confirmed the formation of pure, stoichiometric, and polycrystalline ZnO films using all four Zn precursors. Although the selected precursors are chemically diverse Zn compounds, they all yielded saturating ALD processes and high-quality ZnO thin films at 200 °C. This study highlights the potential benefits of alternative zinc precursors in designing ALD processes for ZnO thin films.

Polymeric substrates are increasingly significant in flexible and implantable electronics. However, the glass transition temperature of polymers like Parylene-C limits their thermal budget and complicates the deposition of high-quality dielectric thin films. Among candidate materials for these applications, tantalum pentoxide $\left(\mathbf{T a}_{\mathbf{2}} \mathbf{O}_{\mathbf{5}}\right)$ is particularly interesting due to its dielectric properties, chemical stability, and biocompatibility for implantable devices. However, $\mathbf{T a}_{\mathbf{2}} \mathbf{O}_{\mathbf{5}}$ atomic layer deposition (ALD) is typically performed at high temperatures, which challenge temperature-sensitive polymer substrates. Here, we investigate the feasibility of lowtemperature thermal $\mathbf{T a}_{\mathbf{2}} \mathbf{O}_{\mathbf{5}}$ ALD at 80 °C using tris(tertbutoxy)-tris(ethylmethylamino)tantalum as the tantalum precursor and H2O as the co-reactant, targeting polymercompatible integration with Parylene-C. Feasibility was assessed by analyzing temperature-dependent film growth on silicon reference substrates as well as structural and morphological properties of representative $\mathbf{T a}_{\mathbf{2}} \mathbf{O}_{\mathbf{5}}$ coatings on Parylene-C. The results identify $\mathbf{T a}_{\mathbf{2}} \mathbf{O}_{\mathbf{5}}$ deposited at $\mathbf{8 0}^{\circ} \mathbf{C}$ by ALD as a promising route toward polymer-compatible deposition.

Atomic/molecular layer deposition (ALD/MLD) offers a comprehensive process and application portfolio for metal-organic thin films; however, ALD/MLD process development for transition-metal-based materials remains very limited, despite the versatile functional properties of their compounds. In this work, to enrich the chemistry of transition metal precursors in ALD/MLD, an all-nitrogen-coordinated cobalt complex, Co(tmsaedma)(2) (tmsaedma = Bis(N,N-dimethyl(N'-trimethylsilyl)ethane-1-amino-2-amido), was employed as the metal precursor for the first time. The Co-N coordination provides an optimal reactive site for a variety of organic linker groups, as demonstrated here by three organic precursors that share the same rigid benzene backbone but differ in reactive groups: 1,4-benzenediol (hydroquinone; HQ), 1,4-benzenedithiol (BDT), and 1,4-benzenedicarboxylic acid (terephthalic acid; BDC). A comprehensive set of characterization techniques, combined with first principles density functional theory (DFT) calculations, is used to systematically investigate the three new ALD/MLD processes and the stability of the resulting Co(II)-organic thin films: Co-HQ, Co-BDT, and Co-BDC. The reactivity and stability trends of the organics are found as BDC>HQ>BDT and BDC>>BDT>>HQ, respectively. Decomposition mechanisms are provided for Co-HQ and Co-BDT. Furthermore, the preparation of low-density, porous CoO thin films with tunable structural and optical properties, difficult to achieve otherwise, is demonstrated via calcination in N-2 of the Co-BDC thin films.

Germanium oxide thin films are promising for advanced applications such as microelectronics, optoelectronics, high-power electronics, optics, and biomedical uses. However, scalable and controlled low-temperature synthesis of GeO2 thin films via atomic layer deposition (ALD) is limited by the small range of available Ge precursors. We introduce monomeric tetrakis-3-(N,N-dimethylamino)propyl germanium(IV) [Ge(DMP)4] as a promising Ge precursor. It is non-pyrophoric, thermally stable, and liquid, and can be obtained in high purity on a multigram scale through an industrially feasible synthesis. Using density functional theory (DFT) and mass spectrometry (MS), we rationalize the coordination environment and identify a feasible chemisorption pathway, indicating a high reactivity of the precursor. Subsequently, [Ge(DMP)4] was employed in low-temperature plasma-enhanced ALD (PEALD) over a wide temperature range from 40°C to 240°C, yielding smooth, uniform germanium oxide films. Rapid and homogeneous nucleation leads to dense films with sub-nanometer thickness. By adjusting the deposition temperature and plasma duration, the film composition could be readily tuned from GeO2 to sub-stoichiometric GeOx. These findings establish [Ge(DMP)4] as an effective, scalable precursor for low-temperature ALD of GeO2, emphasizing the critical role of precursor chemistry in ALD process development.