Search results for "sinkkioksidi"
showing 6 items of 6 documents
Cellulose-inorganic hybrids of strongly reduced thermal conductivity
2022
Abstract The employment of atomic layer deposition and spin coating techniques for preparing inorganic-organic hybrid multilayer structures of alternating ZnO-CNC layers was explored in this study. Helium ion microscopy and X-ray reflectivity showed the superlattice formation for the nanolaminate structures and atomic force microscopy established the efficient control of the CNCs surface coverage on the Al-doped ΖnO by manipulating the concentration of the spin coating solution. Thickness characterization of the hybrid structures was performed via both ellipsometry and X-ray reflectivity and the thermal conductivity was examined by time domain thermoreflectance technique. It appears that ev…
Room-temperature plasma-enhanced atomic layer deposition of ZnO: Film growth dependence on the PEALD reactor configuration
2017
Room-temperature plasma-enhanced atomic layer deposition (PEALD) of ZnO was studied by depositing the films using diethylzinc and O2 plasma from inductively-coupled plasma (ICP) and capacitively-coupled plasma (CCP) plasma source configurations. The CCP-PEALD was operated using both remote and direct plasma. It was observed that the films deposited by means of remote ICP and CCP were all highly oxygen rich, independently on plasma operation parameters, but impurity (H, C) contents could be reduced by increasing plasma pulse time and applied power. With the direct CCP-PEALD the film composition was closer to stoichiometric, and film crystallinity was enhanced. The ZnO film growth was observe…
Hydrogen and Deuterium Incorporation in ZnO Films Grown by Atomic Layer Deposition
2021
Zinc oxide (ZnO) thin films were grown by atomic layer deposition using diethylzinc (DEZ) and water. In addition to depositions with normal water, heavy water (2H2O) was used in order to study the reaction mechanisms and the hydrogen incorporation at different deposition temperatures from 30 to 200 °C. The total hydrogen concentration in the films was found to increase as the deposition temperature decreased. When the deposition temperature decreased close to room temperature, the main source of impurity in hydrogen changed from 1H to 2H. A sufficiently long purging time changed the main hydrogen isotope incorporated in the film back to 1H. A multiple short pulse scheme was used to study th…
Effect of atomic layer deposited zinc promoter on the activity of copper-on-zirconia catalysts in the hydrogenation of carbon dioxide to methanol
2023
Funding Information: The work at Aalto University has been financially supported by the Academy of Finland (COOLCAT consortium, decision no. 329977 and 329978 ; ALDI consortium, decision no. 331082 ). This work made use of Aalto University Bioeconomy, OtaNano and RawMatters infrastructure. Hannu Revitzer (Aalto University) is thanked for the ICP-OES analysis, Aalto workshop people (especially Seppo Jääskeläinen) for working on the reactor modifications. The DFT calculations were made possible by computational resources provided by the CSC — IT Center for Science, Espoo, Finland ( https://www.csc.fi/en/ ) and computer capacity from the Finnish Grid and Cloud Infrastructure (urn:nbn:fi:resear…
Production of ethyl lactate by activated carbon-supported Sn and Zn oxide catalysts utilizing lignocellulosic side streams
2021
In this study, activated carbon-supported Sn and Zn oxide catalysts were prepared from hydrolysis lignin and used for the conversion of model solutions of trioses, hexoses, and lignocellulosic biomass hydrolysates to ethyl lactate. Both catalysts, SnO2@AC and ZnO@AC, were able to produce ethyl lactate in high yields. SnO2@AC was a more active and selective catalyst in triose (dihydroxyacetone) conversion, providing 99% yield to ethyl lactate. ZnO@AC, by contrast, was more selective in glucose and hydrolysate conversion, with a yield of 60% and 85%, respectively. The ethyl lactate yields were significantly higher than those from the optimized model solution experiments when using ZnO@AC cata…
Low-temperature thermal and plasma-enhanced atomic layer deposition of metal oxide thin films
2017
Atomic layer deposition (ALD) is a method for thin film fabrication with atomic level precision. This thesis focuses on low-temperature thermal and plasma- enhanced ALD and presents results on thin film growth by these techniques with examples of common ALD materials: Al2O3, ZnO and TiO2. As an example of limitations of the thermal ALD the nucleation and growth of Al2O3 and ZnO films on different grades of poly(methyl methacrylate) (PMMA) are presented, showing that the initiation of the growth is strongly dependent on both the deposited material and the substrate. A potential application of the ALD ZnO films in polymer surface functionalization is demonstrated by changing in the surface wettab…