Article
Chemistry, Multidisciplinary
Chanwoo Park, Heenang Choi, Ga Yeon Lee, Bo Keun Park, Taek-Mo Chung
Summary: Novel barium heteroleptic complexes were synthesized by substituting the bis(trimethylsilyl)amide of Ba(btsa)(2)center dot 2DME with aminoalkoxide and beta-diketonate ligands. The obtained compounds [Ba(ddemap)(tmhd)](2) (1) and [Ba(ddemmp)(tmhd)](2) (2) were analyzed through various techniques. Complex 1 exhibited a dimeric structure with mu(2)-O bonds in single-crystal X-ray crystallography. These complexes have high volatility and can be used as precursors for the growth of barium-containing thin films.
Article
Chemistry, Physical
Chun-Yuan Wang, Chun-Yi Chou, Han-Fang Shiue, Hsing-Yang Chen, Chen-Hsiang Ling, Jing-Jong Shyue, Miin-Jang Chen
Summary: In this paper, the authors investigate a method to alter the work function of TiN thin films using atomic layer annealing (ALA) technique. The results show that by incorporating layer-by-layer atomic layer deposition cycle with argon plasma treatment, the density, stoichiometry, and crystallinity of TiN thin films can be significantly improved at a low temperature of 300 degrees C, resulting in a wide tunability of the TiN metal gate's work function.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Vladyslav Matkivskyi, Oskari Leiviska, Sigurd Wenner, Hanchen Liu, Ville Vahanissi, Hele Savin, Marisa Di Sabatino, Gabriella Tranell
Summary: This study investigated the application of two widely used atomic layer deposition precursors, TDMA-Ti and TiCl4, in TiOx-based thin films as a passivating contact material for solar cells. It was found that both precursors are suitable for similar deposition temperatures (150 °C). Post-deposition annealing significantly improved the passivation properties of the TiOx film, increasing the minority carrier lifetime (tau(eff)) by over 200 μs.AlOy/TiOx stack reduced the sheet resistance by 40% compared to pure TiOx. The passivation quality of the (AlOy/TiOx) stack was found to depend on the precursor and the ratio of AlOy to TiOx deposition cycles.
Article
Materials Science, Multidisciplinary
Denis Nazarov, Lada Kozlova, Aida Rudakova, Elena Zemtsova, Natalia Yudintceva, Elizaveta Ovcharenko, Alexandra Koroleva, Igor Kasatkin, Ludmila Kraeva, Elizaveta Rogacheva, Maxim Maximov
Summary: Atomic layer deposition (ALD) was used to grow zinc-titanium oxide nanofilms with different ratios of ZnO and TiO2. Characterization techniques such as spectral ellipsometry, X-ray reflectometry, X-ray diffraction, scanning electron microscopy, SEM-EDX, and contact angle measurements were used to evaluate the thickness, morphology, and composition of the films. The results showed that the thickness of the coatings deviated from the rule of mixtures, with higher ZnO/TiO2 ratios resulting in lower thickness and higher titanium oxide content leading to increased thickness. The ZTO samples also exhibited antibacterial properties and did not negatively affect human mesenchymal stem cells, suggesting their potential for medical applications.
Article
Chemistry, Physical
Renjing Huang, Ohhun Kwon, Chao Lin, Raymond J. Gorte
Summary: The study compared the HDO of m-cresol using Pt/Nb2O5/MgAl2O4 and Pt/TiO2/MgAl2O4 catalysts, finding that Pt/Nb2O5/MgAl2O4 catalyst showed better coke tolerance and higher selectivity towards toluene production than Pt/MgAl2O4.
JOURNAL OF CATALYSIS
(2021)
Article
Materials Science, Multidisciplinary
Joonas Merisalu, Tonis Arroval, Aarne Kasikov, Jekaterina Kozlova, Mihkel Rahn, Peeter Ritslaid, Jaan Aarik, Aile Tamm, Kaupo Kukli
Summary: Resistive-switching Al2O3-doped TiO2 thin films were grown by atomic layer deposition, and the electrical properties were tuned by adjusting the aluminum content and distribution, enabling multilevel resistive switching.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Biochemistry & Molecular Biology
Elina Kylmaoja, Jani Holopainen, Faleh Abushahba, Mikko Ritala, Juha Tuukkanen
Summary: Hydroxyapatite (HA) coatings prepared using atomic layer deposition (ALD) show good biocompatibility in terms of cell adhesion and viability, opening up new possibilities for developing improved implant coatings.
Review
Chemistry, Physical
Daniel Attila Karajz, Imre Miklos Szilagyi
Summary: This article reviews the possibilities of photocatalytically active ZnO nanomaterials synthesized using atomic layer deposition (ALD). ZnO, a widely researched photocatalytic material, is influenced by factors such as structure and morphology. The discussion includes the structural possibilities and the incorporation of other materials (such as elements, metals, or semiconductors) to form composite materials, such as ZnO/TiO2 heterostructures, polymer fibers, carbon nanomaterials (e.g. carbon nanotubes or graphene-oxide), and biomaterials.
SURFACES AND INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
H. A. Borbon-Nunez, J. Muniz, A. G. El Hachimi, D. Frausto-Silva, J. L. Gutierrez-Diaz, D. Dominguez, H. Tiznado, A. K. Cuentas-Gallegos
Summary: This study presents the chemical affinity of functional nanostructured materials based on nanoporous carbon and titanium oxide. It demonstrates that modifying nanoporous carbon and nucleating titanium oxide can enhance the electrochemical performance by analyzing the affinity of functional groups on TiO2 nucleation. The effective grafting of TiO2 with the cp-COOH functional group was confirmed through experimental observations and Density Functional Theory calculations.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Materials Science, Ceramics
Chia-Hsun Hsu, Zhi-Xuan Zhang, Pao-Hsun Huang, Wan-Yu Wu, Sin-Liang Ou, Shui-Yang Lien, Chien-Jung Huang, Ming-Kwei Lee, Wen-Zhang Zhu
Summary: In this study, SnO2 films were prepared using PEALD with TDMA-Sn as the metal source and O-2/Ar mixture as the oxidant. It was found that plasma power significantly influences the properties of the SnO2 films, with 1500 W being the optimal power. Lower and higher powers result in unwanted Sn3O4 formation and reduced film quality.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Multidisciplinary
Chia-Hsun Hsu, Ka-Te Chen, Ling-Yan Lin, Wan-Yu Wu, Lu-Sheng Liang, Peng Gao, Yu Qiu, Xiao-Ying Zhang, Pao-Hsun Huang, Shui-Yang Lien, Wen-Zhang Zhu
Summary: Tantalum-doped titanium oxide thin films grown by plasma enhanced atomic layer deposition show reduced crystallinity, lower resistivity, and improved performance as electron transport layer in perovskite solar cells compared to undoped films. The presence of tantalum introduces oxygen vacancies defects and shifts the valance band position, beneficial for band alignment engineering in solar cell applications.
Article
Nanoscience & Nanotechnology
Hae Won Cho, Pavan Pujar, Minsu Choi, Seunghun Kang, Seongin Hong, Junwoo Park, Seungho Baek, Yunseok Kim, Jaichan Lee, Sunkook Kim
Summary: The direct growth of polar orthorhombic phase in Hf0.5Zr0.5O2 (HZO) thin films using Pulsed Laser Deposition (PLD) has been reported. The PLD-HZO technique, integrated with HfO2 dielectric, has shown promising results for low power integrated digital/analog circuits.
NPJ 2D MATERIALS AND APPLICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Lauri Palmolahti, Harri Ali-Loytty, Markku Hannula, Jesse Saari, Weimin Wang, Antti Tukiainen, Kimmo Lahtonen, Mika Valden
Summary: This study investigated the effect of growth temperature on precursor traces in ALD TiO2 films and thermally-induced processes, demonstrating that increasing growth temperature reduced N bearing precursor traces and made TiO2 more easily reducible. Vacuum annealing of TiO2 influenced crystallization and defect formation, with different nitrogen content resulting in different crystalline forms.
Article
Chemistry, Physical
Hong Keun Chung, Sung Ok Won, Yongjoo Park, Jin-Sang Kim, Tae Joo Park, Seong Keun Kim
Summary: TiO2 films were deposited by Atomic Layer Deposition (ALD) using (CpMe5)Ti(OMe)(3) as precursor and O-3 as co-reactant, showing high thermal stability and a wide temperature range. With increasing growth temperature, impurity content decreased, grain size reduced, and a uniform morphology with fine grains was achieved at temperatures above 300 degrees C.
APPLIED SURFACE SCIENCE
(2021)
Article
Engineering, Electrical & Electronic
Chun-Yuan Wang, Chin- Wang, Sheng-Han Yi, Teng-Jan Chang, Chun-Yi Chou, Yu-Tung Yin, Hsin-Chih Lin, Miin-Jang Chen
Summary: The crystalline phases and dielectric properties of ZrO2 thin films can be tailored by capping a nanoscale TiN layer prepared by plasma-enhanced atomic layer deposition. The in-plane tensile strain induced by the TiN capping layer leads to a dramatic paraelectric-to-antiferroelectric phase transformation in ZrO2 and a significant capacitance enhancement. This study demonstrates that the as-deposited TiN capping layer can effectively modulate the dielectric properties of nanoscale thin films without postannealing treatment, benefiting various applications such as supercapacitors and nanoelectronics.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Saba Ghafourisaleh, Marko Vehkamaki, Anton Vihervaara, Chao Zhang, Mikko J. Heikkila, Markku Leskela, Matti Putkonen, Mikko Ritala
Summary: This paper reports the deposition of pyrrone thin film materials using molecular layer deposition (MLD) with pyromellitic dianhydride (PMDA) and 3,3'-diaminobenzidine (DAB) as monomers and ozone as a promoter. Various precursor pulsing sequences are tested, resulting in different growth rates of the films. The films exhibit stability and withstand high temperatures when annealed in air.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Alexander Weiss, Jacqueline Goldmann, Sakari Kettunen, Georgi Popov, Tomi Iivonen, Miika Mattinen, Pasi Jalkanen, Timo Hatanpaa, Markku Leskela, Mikko Ritala, Marianna Kemell
Summary: This study demonstrates a scalable and conformal deposition of copper iodide (CuI) thin films using atomic layer deposition (ALD). The two-step ALD process, involving deposition of CuO and subsequent conversion to CuI using HI vapor, results in phase-pure, uniform, and high-purity CuI films. The successful deposition of CuI on various substrates and its application in diode structures and perovskite solar cells suggests that the ALD-based approach offers a viable alternative for depositing transparent conductive p-type CuI thin films in complex high aspect ratio structures and large substrate areas.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Coatings & Films
Heta-Elisa Nieminen, Mykhailo Chundak, Mikko J. Heikkila, Paloma Ruiz Karkkainen, Marko Vehkamaki, Matti Putkonen, Mikko Ritala
Summary: This paper introduces a vacuum cluster tool specifically designed for studying reaction mechanisms in atomic layer deposition (ALD) and atomic layer etching (ALE) processes. The tool connects a commercial flow-type ALD reactor to a set of UHV chambers, allowing versatile surface characterization without breaking the vacuum environment. The tool enables the study of surface composition and reaction intermediates formed during precursor or etchant pulses in conditions close to true ALD and ALE processing.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Biochemistry & Molecular Biology
Elina Kylmaoja, Faleh Abushahba, Jani Holopainen, Mikko Ritala, Juha Tuukkanen
Summary: Coating bone implants with hydroxyapatite (HA) has benefits for osseointegration, but there may be differences in monocyte differentiation and material resorption compared to natural bone. In this study, ALD-HA coating on a titanium substrate was compared with bovine bone, and it was found that ALD-HA led to the presence of non-resorbing cells instead of resorbing osteoclasts. The topographical properties of ALD-HA, such as surface roughness, may play a role in this cellular reaction.
Article
Chemistry, Multidisciplinary
Xinzhi Li, Marko Vehkamaki, Mykhailo Chundak, Kenichiro Mizohata, Anton Vihervaara, Markku Leskela, Matti Putkonen, Mikko Ritala
Summary: This paper presents the preparation process and characterization of boron-doped Al2O3 thin films using atomic layer deposition. The effects of deposition temperature and annealing process on the properties of the films are investigated. The boron-doped Al2O3 film deposited at 200 degrees C shows low leakage current and a dielectric constant of 5.18 when the film thickness is 70 nm.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Engineering, Environmental
Johanna Paajanen, Lauri Pettila, Satu Lonnrot, Mikko Heikkila, Timo Hatanpa, Mikko Ritala, Risto Koivula
Summary: Nuclear power is a clean energy source, but it produces hazardous fission products such as 90Sr. Researchers have developed submicron TiO2 and TiO2/SiO2 composite fibers to remove Sr2+ from water. These fibers showed excellent Sr2+ adsorption capacity, and the hydrothermally modified TiO2 fibers had the highest distribution coefficient. The nanorods on the fibers also remained undamaged in column operation tests, making them promising for industrial wastewater treatment.
CHEMICAL ENGINEERING JOURNAL ADVANCES
(2023)
Article
Chemistry, Physical
Alexander Weiss, Mariia Terletskaia, Georgi Popov, Kenichiro Mizohata, Markku Leskela, Mikko Ritala, Marianna Kemell
Summary: This study addresses the limited ability to deposit conformal and scalable halide perovskite thin films by using atomic layer deposition (ALD). Two new ALD processes, SnI2 and CsSnI3, are presented in order to achieve lead-free and environmentally friendly absorber layers for perovskite solar cells (PSCs). The findings demonstrate the successful deposition of phase-pure gamma-CsSnI3 films through conversion reactions and propose an alternative method using pulsed chemical vapor deposition (pulsed CVD) SnI2 step.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Valtteri Lasonen, Anton Vihervaara, Georgi Popov, Eva Tois, Lars Mester, Mohammad Karimi, Yoana Ilarionova, Reza Jafari Jam, Jonas Sundqvist, Mikko Ritala
Summary: Area-selective etching (ASE) of polymers is a novel and simple self-aligned patterning technique with potential application in semiconductor device fabrication. The polymer film is selectively decomposed on top of catalytically active materials while staying intact on catalytically inactive materials, eliminating edge placement errors and defects. This study investigates the ASE of poly(methyl methacrylate) (PMMA) using various catalytic materials in different atmospheres. The feasibility of the entire patterning process is demonstrated on a 100 nanometer scale.
CHEMISTRY OF MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Xinzhi Li, Marko Vehkamaki, Mykhailo Chundak, Kenichiro Mizohata, Anton Vihervaara, Matti Putkonen, Markku Leskela, Mikko Ritala
Summary: This article presents a study on a new type of inorganic-organic silicon-based molecular layer deposition (MLD) process, using AlCl3 and BTEB as precursors. The researchers successfully deposited hybrid films with high growth per cycle (GPC). FESEM and AFM were used to analyze the surface morphology of the films, while ATR-FTIR, ToF-ERDA, and XPS were employed to analyze the structure and composition. The storage environment of the films was found to significantly affect their performance.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2023)
Article
Chemistry, Inorganic & Nuclear
Elisa Atosuo, Miia Maentymaeki, Leevi Pesonen, Kenichiro Mizohata, Timo Hatanpaa, Markku Leskelae, Mikko Ritala
Summary: The present study investigates the atomic layer deposition (ALD) of CoF2, NiF2, and HoF3 thin films. CoF2 deposition was achieved using CoCl2(TMEDA) and NH4F as precursors, resulting in tetragonal CoF2 films with a growth per cycle (GPC) of 0.7-1.2 Å. NiF2 deposition utilized Ni(thd)(2) and TaF5 or NbF5 as precursors, producing tetragonal NiF2 films with high oxygen and hydrogen contents. HoF3 films were deposited using Ho(thd)(3) and NbF5 as precursors, yielding orthorhombic HoF3 films with low impurity contents.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Physical
Anton Vihervaara, Timo Hatanpaa, Heta-Elisa Nieminen, Kenichiro Mizohata, Mykhailo Chundak, Mikko Ritala
Summary: In this study, high purity gold films were successfully deposited on various substrate materials for the first time using thermal reductive atomic layer deposition method. The precursors used were AuCl-(PEt3) and 1,4-bis-(trimethylgermyl)-1,4-dihydropyrazine. The growth rate was measured to be 1.7 angstroms per cycle after full coverage of the film. The films exhibited low resistivity close to the bulk value and minimal impurity content. The reaction mechanism of the process was studied in situ using a quartz crystal microbalance and a quadrupole mass spectrometer.
