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Rahman T, Martin NP, Jenkins JK, Elzein R, Fast DB, Addou R, Herman GS, Nyman M. Nb 2O 5, LiNbO 3, and (Na, K)NbO 3 Thin Films from High-Concentration Aqueous Nb-Polyoxometalates. Inorg Chem 2022; 61:3586-3597. [PMID: 35148102 DOI: 10.1021/acs.inorgchem.1c03638] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthesizing functional materials from water contributes to a sustainable energy future. On the atomic level, water drives complex metal hydrolysis/condensation/speciation, acid-base, ion pairing, and solvation reactions that ultimately direct material assembly pathways. Here, we demonstrate the importance of Nb-polyoxometalate (Nb-POM) speciation in enabling deposition of Nb2O5, LiNbO3, and (Na, K)NbO3 (KNN) from high-concentration solutions, up to 2.5 M Nb for Nb2O5 and ∼1 M Nb for LiNbO3 and KNN. Deposition of KNN from 1 M Nb concentration represents a potentially important advancment in lead-free piezoelectrics, an application that requires thick films. Solution characterization via small-angle X-ray scattering and Raman spectroscopy described the speciation for all precursor solutions as the [HxNb24O72](x-24) POM, as did total pair distribution function analyses of X-ray scattering of amorphous gels prior to conversion to oxides. The tendency of the Nb24-POM to form extended networks without crystallization leads to conformal and well-adhered films. The films were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, ellipsometry, and X-ray photoelectron spectroscopy. As a strategy to convert aqueous deposition solutions from {Nb10}-POMs to {Nb24}-POMs, we devised a general procedure to produce doped Nb2O5 thin films including Ca, Ag, and Cu doping.
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Affiliation(s)
- Tasnim Rahman
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Nicolas P Martin
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Jessica K Jenkins
- School of Chemical, Biological, and Environmental Engineering, 116 Johnson Hall, 105 SW 26th St. Corvallis, Oregon 97331, United States
| | - Radwan Elzein
- School of Chemical, Biological, and Environmental Engineering, 116 Johnson Hall, 105 SW 26th St. Corvallis, Oregon 97331, United States
| | - Dylan B Fast
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Rafik Addou
- School of Chemical, Biological, and Environmental Engineering, 116 Johnson Hall, 105 SW 26th St. Corvallis, Oregon 97331, United States
| | - Gregory S Herman
- School of Chemical, Biological, and Environmental Engineering, 116 Johnson Hall, 105 SW 26th St. Corvallis, Oregon 97331, United States
| | - May Nyman
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
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Burns SR, Dolgos MR. Sizing up (K 1−xNa x)NbO 3 films: a review of synthesis routes, properties & applications. NEW J CHEM 2021. [DOI: 10.1039/d1nj01092a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This review discusses (K,Na)NbO3 thin films, with a focus on synthesis, chemically modifying properties, plus piezoelectric and biomedical KNN devices.
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Blichfeld AB, Bakken K, Chernyshov D, Glaum J, Grande T, Einarsrud MA. Experimental setup for high-temperature in situ studies of crystallization of thin films with atmosphere control. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1209-1217. [PMID: 32876595 PMCID: PMC7467347 DOI: 10.1107/s1600577520010140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Understanding the crystallization process for chemical solution deposition (CSD) processed thin films is key in designing the fabrication strategy for obtaining high-quality devices. Here, an in situ sample environment is presented for studying the crystallization of CSD processed thin films under typical processing parameters using near-grazing-incidence synchrotron X-ray diffraction. Typically, the pyrolysis is performed in a rapid thermal processing (RTP) unit, where high heating rates, high temperatures and atmosphere control are the main control parameters. The presented in situ setup can reach heating rates of 20°C s-1 and sample surface temperatures of 1000°C, comparable with commercial RTP units. Three examples for lead-free ferroelectric thin films are presented to show the potential of the new experimental set-up: high temperature, for crystallization of highly textured Sr0.4Ba0.6Nb2O6 on a SrTiO3 (001) substrate, high heating rate, revealing polycrystalline BaTiO3, and atmosphere control with 25% CO2, for crystallization of BaTiO3. The signal is sufficient to study a single deposited layer (≥10 nm for the crystallized film) which then defines the interface between the substrate and thin film for the following layers. A protocol for processing the data is developed to account for a thermal shift of the entire setup, including the sample, to allow extraction of maximum information from the refinement, e.g. texture. The simplicity of the sample environment allows for the future development of even more advanced measurements during thin-film processing under non-ambient conditions.
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Affiliation(s)
- Anders Bank Blichfeld
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Sem Saelands vei 12, Trondheim 7491, Norway
| | - Kristine Bakken
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Sem Saelands vei 12, Trondheim 7491, Norway
| | - Dmitry Chernyshov
- Swiss–Norwegian Beamlines, European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38043, France
| | - Julia Glaum
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Sem Saelands vei 12, Trondheim 7491, Norway
| | - Tor Grande
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Sem Saelands vei 12, Trondheim 7491, Norway
| | - Mari-Ann Einarsrud
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Sem Saelands vei 12, Trondheim 7491, Norway
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Helth Gaukås N, Dale SM, Ræder TM, Toresen A, Holmestad R, Glaum J, Einarsrud MA, Grande T. Controlling Phase Purity and Texture of K 0.5Na 0.5NbO 3 Thin Films by Aqueous Chemical Solution Deposition. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2042. [PMID: 31247910 PMCID: PMC6651159 DOI: 10.3390/ma12132042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/20/2019] [Accepted: 06/20/2019] [Indexed: 11/28/2022]
Abstract
Aqueous chemical solution deposition (CSD) of lead-free ferroelectric K0.5Na0.5NbO3 (KNN) thin films has a great potential for cost-effective and environmentally friendly components in microelectronics. Phase purity of KNN is, however, a persistent challenge due to the volatility of alkali metal oxides, usually countered by using excess alkali metals in the precursor solutions. Here, we report on the development of two different aqueous precursor solutions for CSD of KNN films, and we demonstrate that the decomposition process during thermal processing of the films is of detrimental importance for promoting nucleation of KNN and suppressing the formation of secondary phases. Based on thermal analysis, X-ray diffraction and IR spectroscopy of films as well as powders prepared from the solutions, it was revealed that the decomposition temperature can be controlled by chemistry resulting in phase pure KNN films. A columnar microstructure with out-of-plane texturing was observed in the phase pure KNN films, demonstrating that the microstructure is directly coupled to the thermal processing of the films.
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Affiliation(s)
- Nikolai Helth Gaukås
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Silje Marie Dale
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Trygve Magnus Ræder
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Andreas Toresen
- Department of Physics, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Randi Holmestad
- Department of Physics, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Julia Glaum
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Mari-Ann Einarsrud
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Tor Grande
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
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