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Ekström E, le Febvrier A, Bourgeois F, Lundqvist B, Palisaitis J, Persson POÅ, Caballero-Calero O, Martín-González MS, Klarbring J, Simak SI, Eriksson F, Paul B, Eklund P. The effects of microstructure, Nb content and secondary Ruddlesden–Popper phase on thermoelectric properties in perovskite CaMn1−xNbxO3 (x = 0–0.10) thin films. RSC Adv 2020; 10:7918-7926. [PMID: 35492179 PMCID: PMC9049944 DOI: 10.1039/c9ra10007e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/14/2020] [Indexed: 11/21/2022] Open
Abstract
Reduction of thermal conductivity of sputtered CaMn1−xNbxO3 thin films by secondary Ruddlesden–Popper phase and grain size optimization.
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Affiliation(s)
- E. Ekström
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - A. le Febvrier
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | | | - B. Lundqvist
- Semiconductor Materials Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - J. Palisaitis
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - P. O. Å. Persson
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - O. Caballero-Calero
- IMN-Instituto de Micro y Nanotecnología
- IMN-CNM
- CSIC (CEI UAM+CSIC) Isaac Newton
- Madrid
- Spain
| | - M. S. Martín-González
- IMN-Instituto de Micro y Nanotecnología
- IMN-CNM
- CSIC (CEI UAM+CSIC) Isaac Newton
- Madrid
- Spain
| | - J. Klarbring
- Theoretical Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - S. I. Simak
- Theoretical Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - F. Eriksson
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - B. Paul
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
| | - P. Eklund
- Thin Film Physics Division
- Department of Physics, Chemistry and Biology (IFM)
- Linköping University
- SE-58183 Linköping
- Sweden
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2
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Lu J, Persson I, Lind H, Palisaitis J, Li M, Li Y, Chen K, Zhou J, Du S, Chai Z, Huang Z, Hultman L, Eklund P, Rosen J, Huang Q, Persson POÅ. Ti n+1C n MXenes with fully saturated and thermally stable Cl terminations. Nanoscale Adv 2019; 1:3680-3685. [PMID: 36133532 PMCID: PMC9417890 DOI: 10.1039/c9na00324j] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/08/2019] [Indexed: 05/19/2023]
Abstract
MXenes are a rapidly growing family of 2D materials that exhibit a highly versatile structure and composition, allowing for significant tuning of the materials properties. These properties are, however, ultimately limited by the surface terminations, which are typically a mixture of species, including F and O that are inherent to the MXene processing. Other and robust terminations are lacking. Here, we apply high-resolution scanning transmission electron microscopy (STEM), corresponding image simulations and first-principles calculations to investigate the surface terminations on MXenes synthesized from MAX phases through Lewis acidic melts. The results show that atomic Cl terminates the synthesized MXenes, with mere residual presence of other termination species. Furthermore, in situ STEM-electron energy loss spectroscopy (EELS) heating experiments show that the Cl terminations are stable up to 750 °C. Thus, we present an attractive new termination that widely expands the MXenes' functionalization space and enables new applications.
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Affiliation(s)
- J Lu
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - I Persson
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - H Lind
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - J Palisaitis
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - M Li
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - Y Li
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - K Chen
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - J Zhou
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - S Du
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - Z Chai
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - Z Huang
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - L Hultman
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - P Eklund
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - J Rosen
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
| | - Q Huang
- Engineering Laboratory of Advanced Energy Materials (FiNE Lab.), Ningbo Institute of Industrial Technology, Chinese Academy of Sciences Ningbo Zhejiang 315201 China
| | - P O Å Persson
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University SE-581 83 Linköping Sweden
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3
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Ghafoor N, Petrov I, Holec D, Greczynski G, Palisaitis J, Persson POA, Hultman L, Birch J. Self-structuring in Zr 1-xAl xN films as a function of composition and growth temperature. Sci Rep 2018; 8:16327. [PMID: 30397271 PMCID: PMC6218527 DOI: 10.1038/s41598-018-34279-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/03/2018] [Indexed: 11/19/2022] Open
Abstract
Nanostructure formation via surface-diffusion-mediated segregation of ZrN and AlN in Zr1−xAlxN films during high mobility growth conditions is investigated for 0 ≤ × ≤ 1. The large immiscibility combined with interfacial surface and strain energy balance resulted in a hard nanolabyrinthine lamellar structure with well-defined (semi) coherent c-ZrN and w-AlN domains of sub-nm to ~4 nm in 0.2 ≤ × ≤ 0.4 films, as controlled by atom mobility. For high AlN contents (x > 0.49) Al-rich ZrN domains attain wurtzite structure within fine equiaxed nanocomposite wurtzite lattice. Slow diffusion in wurtzite films points towards crystal structure dependent driving force for decomposition. The findings of unlikelihood of iso-structural decomposition in c-Zr1−xAlxN, and stability of w-Zr1−xAlxN (in large × films) is complemented with first principles calculations.
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Affiliation(s)
- N Ghafoor
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden.
| | - I Petrov
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden.,Materials Science Department, and Frederick Seitz Materials Research Laboratory, University of Illinois, 104 S. Goodwin Avenue, Urbana, Illinois, 61801, USA
| | - D Holec
- Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef-Strasse 18, A-8700, Leoben, Austria
| | - G Greczynski
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden
| | - J Palisaitis
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden
| | - P O A Persson
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden
| | - L Hultman
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden
| | - J Birch
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden
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4
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Abstract
We have examined the early stages of self-induced InAlN core-shell nanorod (NR) formation processes on amorphous carbon substrates in plan-view geometry by means of transmission electron microscopy methods. The results show that the grown structure phase separates during the initial moments of deposition into a majority of Al-rich InAlN and a minority of In-enriched InAlN islands. The islands possess polygonal shapes and are mainly oriented along a crystallographic c-axis. The growth proceeds with densification and coalescence of the In-enriched islands, resulting in a base for the In-enriched NR cores with shape transformation to hexagonal. The Al-rich shell formation around such early cores is observed at this stage. The matured core-shell structure grows axially and radially, eventually reaching a steady growth state which is dominated by the axial NR growth. We discuss the NR formation mechanism by considering the adatom surface kinetics, island surface energy, phase separation of InAlN alloys, and incoming flux directions during dual magnetron sputter epitaxy.
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Affiliation(s)
- J Palisaitis
- Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
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5
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Palisaitis J, Hsiao CL, Hultman L, Birch J, Persson POÅ. Direct observation of spinodal decomposition phenomena in InAlN alloys during in-situ STEM heating. Sci Rep 2017; 7:44390. [PMID: 28290508 PMCID: PMC5349532 DOI: 10.1038/srep44390] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/07/2017] [Indexed: 11/29/2022] Open
Abstract
The spinodal decomposition and thermal stability of thin In0.72Al0.28N layers and In0.72Al0.28N/AlN superlattices with AlN(0001) templates on Al2O3(0001) substrates was investigated by in-situ heating up to 900 °C. The thermally activated structural and chemical evolution was investigated in both plan-view and cross-sectional geometries by scanning transmission electron microscopy in combination with valence electron energy loss spectroscopy. The plan-view observations demonstrate evidence for spinodal decomposition of metastable In0.72Al0.28N after heating at 600 °C for 1 h. During heating compositional modulations in the range of 2–3 nm-size domains are formed, which coarsen with applied thermal budgets. Cross-sectional observations reveal that spinodal decomposition begin at interfaces and column boundaries, indicating that the spinodal decomposition has a surface-directed component.
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Affiliation(s)
- J Palisaitis
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
| | - C-L Hsiao
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
| | - L Hultman
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
| | - J Birch
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
| | - P O Å Persson
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
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Filippov S, Jansson M, Stehr JE, Palisaitis J, Persson POÅ, Ishikawa F, Chen WM, Buyanova IA. Strongly polarized quantum-dot-like light emitters embedded in GaAs/GaNAs core/shell nanowires. Nanoscale 2016; 8:15939-15947. [PMID: 27537077 DOI: 10.1039/c6nr05168e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent developments in fabrication techniques and extensive investigations of the physical properties of III-V semiconductor nanowires (NWs), such as GaAs NWs, have demonstrated their potential for a multitude of advanced electronic and photonics applications. Alloying of GaAs with nitrogen can further enhance the performance and extend the device functionality via intentional defects and heterostructure engineering in GaNAs and GaAs/GaNAs coaxial NWs. In this work, it is shown that incorporation of nitrogen in GaAs NWs leads to formation of three-dimensional confining potentials caused by short-range fluctuations in the nitrogen composition, which are superimposed on long-range alloy disorder. The resulting localized states exhibit a quantum-dot like electronic structure, forming optically active states in the GaNAs shell. By directly correlating the structural and optical properties of individual NWs, it is also shown that formation of the localized states is efficient in pure zinc-blende wires and is further facilitated by structural polymorphism. The light emission from these localized states is found to be spectrally narrow (∼50-130 μeV) and is highly polarized (up to 100%) with the preferable polarization direction orthogonal to the NW axis, suggesting a preferential orientation of the localization potential. These properties of self-assembled nano-emitters embedded in the GaNAs-based nanowire structures may be attractive for potential optoelectronic applications.
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Affiliation(s)
- S Filippov
- Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden.
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Amloy S, Karlsson KF, Eriksson MO, Palisaitis J, Persson POÅ, Chen YT, Chen KH, Hsu HC, Hsiao CL, Chen LC, Holtz PO. Excitons and biexcitons in InGaN quantum dot like localization centers. Nanotechnology 2014; 25:495702. [PMID: 25410551 DOI: 10.1088/0957-4484/25/49/495702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Indium segregation in a narrow InGaN single quantum well creates quantum dot (QD) like exciton localization centers. Cross-section transmission electron microscopy reveals varying shapes and lateral sizes in the range ∼1-5 nm of the QD-like features, while scanning near field optical microscopy demonstrates a highly inhomogeneous spatial distribution of optically active individual localization centers. Microphotoluminescence spectroscopy confirms the spectrally inhomogeneous distribution of localization centers, in which the exciton and the biexciton related emissions from single centers of varying geometry could be identified by means of excitation power dependencies. Interestingly, the biexciton binding energy (E(b)xx) was found to vary from center to center, between 3 to -22 meV, in correlation with the exciton emission energy. Negative binding energies are only justified by a three-dimensional quantum confinement, which confirms QD-like properties of the localization centers. The observed energy correlation is proposed to be understood as variations of the lateral extension of the confinement potential, which would yield smaller values of E(b)xx for reduced lateral extension and higher exciton emission energy. The proposed relation between lateral extension and E(b)xx is further supported by the exciton and the biexciton recombination lifetimes of a single QD, which suggest a lateral extension of merely ∼3 nm for a QD with strongly negative E(b)xx = -15.5 meV.
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Affiliation(s)
- S Amloy
- Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden. Department of Physics, Faculty of Science, Thaksin University, Phattalung 93110, Thailand.
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Lundskog A, Palisaitis J, Hsu CW, Eriksson M, Karlsson KF, Hultman L, Persson POÅ, Forsberg U, Holtz PO, Janzén E. InGaN quantum dot formation mechanism on hexagonal GaN/InGaN/GaN pyramids. Nanotechnology 2012; 23:305708. [PMID: 22781961 DOI: 10.1088/0957-4484/23/30/305708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Growing InGaN quantum dots (QDs) at the apex of hexagonal GaN pyramids is an elegant approach to achieve a deterministic positioning of QDs. Despite similar synthesis procedures by metal organic chemical vapor deposition, the optical properties of the QDs reported in the literature vary drastically. The QDs tend to exhibit either narrow or broad emission lines in the micro-photoluminescence spectra. By coupled microstructural and optical investigations, the QDs giving rise to narrow emission lines were concluded to nucleate in association with a (0001) facet at the apex of the GaN pyramid.
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Affiliation(s)
- A Lundskog
- Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
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