TY - GEN A1 - Kosto, Yuliia A1 - Morales, Carlos A1 - Devi, Anjana A1 - Henkel, Karsten A1 - Flege, Jan Ingo T1 - Activity of cerium oxide thin films prepared by atomic layer deposition using custom and commercial precursors T2 - Verhandlungen der DPG N2 - Atomic layer deposition (ALD) allows preparation of conformal coatings with possibility to control their thickness at the submonolayer level, making it a good tool for depositing active layers on 3D structures. Our group is working on cerium oxide-based materials for hydrogen detection, which is difficult at ambient conditions due to the low sensitivity and long response time of the sensors. The cerium oxide layers prepared by ALD contain a lot of defects and provide an opportunity to overcome these complications. Thickness and morphology of the oxide films play an important role in defining the Ce3+/Ce4+ ratio, as well as the interface with the used substrate. Here, we compare cerium oxide thin films deposited by ALD techniques on SiO2 and Al2O3 substrates. The results reveal that the interface to the substrate can considerably influence the reactivity of the cerium oxide toward hydrogen and oxygen. Preparation of the oxides using two different precursors (commercial Ce(thd)4 and custom Ce(dpdmg)3) has been demonstrated to affect the redox properties of the films, their reactivity, and the reversibility. KW - Atomic layer deposition KW - Cerium oxide KW - hydrogen detection Y1 - 2023 UR - https://www.dpg-verhandlungen.de/year/2023/conference/skm/part/o/session/42/contribution/4 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Tschammer, Rudi A1 - Kosto, Yuliia A1 - Morales, Carlos A1 - Schmickler, Marcel A1 - Henkel, Karsten A1 - Devi, Anjana A1 - Flege, Jan Ingo T1 - Atomic layer deposition of cerium oxide monitored by operando ellipsometry and in-situ X-ray photoelectron spectroscopy T2 - Verhandlungen der DPG N2 - Atomic layer deposition (ALD) has been used extensively to grow homogeneous films with excellent coverage and atomic-scale thickness control for a variety of applications. However, remaining challenges include the investigation of novel precursor-oxidant combinations for low-temperature deposition as well as unraveling the complex interplay between substrate and coating for ultrathin films. In this work, we present a detailed investigation of ultrathin cerium oxide films grown using the novel Ce(dpdmg)3 precursor with H2O and O2. Following a surface science-based approach, we have combined operando spectroscopic ellipsometry and in-situ X-ray photoelectron spectroscopy to allow rapid process optimization and determination of the complex relation between oxide stoichiometry, film thickness and ALD growth parameters, revealing a distinct dependence of inital Ce3+ content on the film thickness and choice of oxidant. This offers the possibility of adjusting the oxide properties to application requirements e.g. in gas sensing by choosing a suitable precursor-oxidant combination. KW - Atomic layer deposition (ALD) KW - ceria KW - low-temperature deposition KW - operando spectroscopic ellipsometry KW - in-situ X-ray photoelectron spectroscopy KW - film thickness KW - oxidant choice KW - cerium oxidation state Y1 - 2024 UR - https://www.dpg-verhandlungen.de/year/2024/conference/berlin/part/o/session/49/contribution/4 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER -