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Eriksson, Fredrik
Alternative names
Publications (10 of 45) Show all publications
Dorri, S., Nyqvist, O., Palisaitis, J., Vorobiev, A., Devishvili, A., Sandström, P., . . . Birch, J. (2025). Artificial superlattices with abrupt interfaces by monolayer-controlled growth kinetics during magnetron sputter epitaxy, case of hexagonal CrB2/TiB2 heterostructures. Materials & design, 251, Article ID 113661.
Open this publication in new window or tab >>Artificial superlattices with abrupt interfaces by monolayer-controlled growth kinetics during magnetron sputter epitaxy, case of hexagonal CrB2/TiB2 heterostructures
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2025 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 251, article id 113661Article in journal (Refereed) Published
Abstract [en]

Artificial superlattices exhibit exceptional electronic, magnetic, optical, and mechanical properties which make them unique candidates for applications in a broad range of technologies. A common key feature of superlattices is the need for atomically abrupt interfaces. However, superlattices comprised of materials with different properties, such as melting points and diffusivities, pose large challenges for achieving high crystal quality of both constituents with abrupt interfaces. By employing ion-assisted magnetron sputter epitaxy, we present an innovative solution to this problem with utilizing a unique combination of thermal radiation and kinetic energy that enable sufficient adatom mobility for epitaxial growth of both materials. The research was implemented for the case of CrB2/TiB2 heteroepitaxial superlattices, as neutron interference mirrors, wherein the constituents’ melting points differ by 1100 K. Ion-induced intermixing was avoided by commencing growth of each TiB2 and CrB2 layer by up to 3 unit cells (uc) without ion assistance, forming a buffer to protect the interface during the ion-assisted growth of the remainder of each layer. Heteroepitaxial superlattice growth with interface widths σCrB2 ∼1 uc and σTiB2 ∼2 uc was confirmed for different modulation periods. More than 3000 uc (∼1 µm) thick superlattices with abrupt interfaces were demonstrated for neutron mirror applications.

Place, publisher, year, edition, pages
Elsevier, 2025
Keywords
Interface engineering, Magnetron sputtering, Modulated ion-assistance, Neutron optics, Superlattice, Unit cell buffer
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-211662 (URN)10.1016/j.matdes.2025.113661 (DOI)001421830000001 ()2-s2.0-85215987105 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish Foundation for Strategic Research
Note

Funding Agencies|Swedish National Graduate School in Neutron Scattering (SwedNess); Swedish Foundation for Strategic Research (SSF); Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials (AFM) at Linkoping University; Center in Nano-science and technology at LiTH CeNano 2021 and 2022; Society of Vacuum Coaters Foundation (SVCF); Hans Werthen Foundation; Swedish Research Council (VR) [2019-00191]; Swedish National Infrastructure in Advanced Electron Microscopy [2021-00171, RIF21-0026]; Knut and Alice Wallenberg Foundation [KAW 2015.0043]; Swedish neutron reflectometer SuperADAM at ILL [VR 2021-00159];  [GSn15-0008];  [2009 00971]

Available from: 2025-02-14 Created: 2025-02-14 Last updated: 2025-03-05
Dorri, S., Ghafoor, N., Palisaitis, J., Stendahl, S., Devishvili, A., Vorobiev, A., . . . Birch, J. (2024). Enhanced quality of single crystal CrBx/TiBy diboride superlattices by controlling boron stoichiometry during sputter deposition. Applied Surface Science, Article ID 159606.
Open this publication in new window or tab >>Enhanced quality of single crystal CrBx/TiBy diboride superlattices by controlling boron stoichiometry during sputter deposition
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2024 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, article id 159606Article in journal (Refereed) Published
Abstract [en]

Single-crystal CrB2/TiB2 diboride superlattices with well-defined layers are promising candidates for neutron optics. However, excess B in sputter-deposited TiBy using a single TiB2 target deteriorates the structural quality of CrBx/TiBy (0001) superlattices. We study the influence of co-sputtering of TiB2 + Ti on the stoichiometry and crystalline quality of 300-nm-thick TiBy single layers and CrBx/TiBy (0001) superlattices on Al2O3(0001) substrates grown by DC magnetron sputter epitaxy at growth-temperatures TS ranging from 600 to 900 °C. By controlling the relative applied powers to the TiB2 and Ti magnetrons, y could be reduced from 3.3 to 0.9. TiB2.3 grown at 750 °C exhibited epitaxial domains about 10x larger than non-co-sputtered films. Close-to-stoichiometry CrB1.7/TiB2.3 superlattices with modulation periods Λ = 6 nm grown at 750 °C showed the highest single crystal quality and best layer definition. TiB2.3 layers display rough top interfaces indicating kinetically limited growth while CrB1.7 forms flat and abrupt top interfaces indicating epitaxial growth with high adatom mobility.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Superlattice, Diboride, Thin film, Co-sputtering, Nanostructure
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-200730 (URN)10.1016/j.apsusc.2024.159606 (DOI)001183388000001 ()
Note

Funding: Swedish National Graduate School in Neutron Scattering (SwedNess), Swedish Foundation for Strategic Research (SSF) GSn15 - 0008, Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials (AFM) at Linköping University (Faculty Grant SFO Mat LiU No. 2009 00971), Center in Nanoscience and technology at LiTH CeNano, Hans Werthén Foundation (IVA), Society of Vacuum Coaters Foundation (SVCF), Swedish Research Council (VR) Grant numbers 2019-00191 (for accelerator-based ion-technological center in tandem accelerator laboratory in Uppsala University), VR and SSF for access to ARTEMI, the Swedish National Infrastructure in Advanced Electron Microscopy (2021-00171 and RIF21-0026), Knut and Alice Wallenberg Foundation for the support of the electron microscopy laboratory at Linköping University (KAW 2015.0043), VR 2021-00159 for the Swedish neutron reflectometer SuperADAM at ILL 10.5291/ILL-DATA.CRG-2964, and Plansee GmbH for providing diboride targets.

Available from: 2024-02-06 Created: 2024-02-06 Last updated: 2024-11-14Bibliographically approved
Beket, G., Zubayer, A., Zhang, Q., Stahn, J., Eriksson, F., Fahlman, M., . . . Gao, F. (2024). Overcoming the voltage losses caused by the acceptor-based interlayer in laminated indoor OPVs. SMARTMAT, 5(3), Article ID e1237.
Open this publication in new window or tab >>Overcoming the voltage losses caused by the acceptor-based interlayer in laminated indoor OPVs
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2024 (English)In: SMARTMAT, ISSN 2766-8525, Vol. 5, no 3, article id e1237Article in journal (Refereed) Published
Abstract [en]

Harvesting indoor light to power electronic devices for the Internet of Things has become an application scenario for emerging photovoltaics, especially utilizing organic photovoltaics (OPVs). Combined liquid- and solid-state processing, such as printing and lamination used in industry for developing indoor OPVs, also provides a new opportunity to investigate the device structure, which is otherwise hardly possible based on the conventional approach due to solvent orthogonality. This study investigates the impact of fullerene-based acceptor interlayer on the performance of conjugated polymer-fullerene-based laminated OPVs for indoor applications. We observe open-circuit voltage (V-OC) loss across the interface despite this arrangement being presumed to be ideal for optimal device performance. Incorporating insulating organic components such as polyethyleneimine (PEI) or polystyrene (PS) into fullerene interlayers decreases the work function of the cathode, leading to better energy level alignment with the active layer (AL) and reducing the V-OC loss across the interface. Neutron reflectivity studies further uncover two different mechanisms behind the V-OC increase upon the incorporation of these insulating organic components. The self-organized PEI layer could hinder the transfer of holes from the AL to the acceptor interlayer, while the gradient distribution of the PS-incorporated fullerene interlayer eliminates the thermalization losses. This work highlights the importance of structural dynamics near the extraction interfaces in OPVs and provides experimental demonstrations of interface investigation between solution-processed cathodic fullerene layer and bulk heterojunction AL.

Place, publisher, year, edition, pages
WILEY, 2024
Keywords
ideal morphology model; indoor organic photovoltaics; lamination; neutron reflectivity; solution processing
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-197560 (URN)10.1002/smm2.1237 (DOI)001041107300001 ()
Note

Funding Agencies|Swedish Foundation for Strategic Research (SSF) [ID20-0105]; Swedish Research Council [2019 00653]

Available from: 2023-09-07 Created: 2023-09-07 Last updated: 2024-10-25Bibliographically approved
Dorri, S., Palisaitis, J., Kolozsvári, S., Polcik, P., Persson, P., Ghafoor, N., . . . Birch, J. (2024). TiB1.8 single layers and epitaxial TiB2-based superlattices by magnetron sputtering using a TiB (Ti:B = 1:1) target. Surface & Coatings Technology, 494, Article ID 131534.
Open this publication in new window or tab >>TiB1.8 single layers and epitaxial TiB2-based superlattices by magnetron sputtering using a TiB (Ti:B = 1:1) target
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2024 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 494, article id 131534Article in journal (Refereed) Published
Abstract [en]

Sputter-deposited titanium diborides are promising candidates for protective coatings in harsh and extreme conditions. However, growing these layers from TiB2 diboride targets by DC magnetron sputtering usually leads to over-stoichiometric layers with low crystal qualities. Moreover, superlattices with TiB2 as one of the constituents have been becoming popular, owing to their superior mechanical properties compared to single layer constituents in addition to their use in other applications such as neutron optics. Here, we propose the use of a TiB (Ti:B = 1:1) sputtering target in an on-axis deposition geometry and demonstrate the growth of epitaxial sub-stoichiometric TiB1.8 thin films. Furthermore, we present the growth of CrB1.7/TiB1.8 superlattices, from TiB (Ti:B = 1:1) and stoichiometric CrB2 targets, with abrupt interfaces as promising materials system for neutron interference mirrors. The high crystal quality structure with well-defined interfaces is the common feature of superlattices which, regardless of application, should be addressed during the growth process.

Utilizing TiB target, all films crystallize in the hexagonal AlB2 structure. The sub-stoichiometry of the TiB1.8 films was accompanied by the presence of planar defects embedded in the films. CrB1.7/TiB1.8 superlattices exhibited a homogeneous boron distribution within the layers with no sign of B-rich tissue phases through the layers. This study demonstrates the feasibility for TiB as sputter target material, that offers a solution for deposition of TiB2-based superlattices without the need to adjust the deposition parameters. Such adjustments would otherwise be unavoidable for tuning the TiB2 composition and could affect the growth of the other constituent materials.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Titanium diboride, Superlattices, Stoichiometry, Magnetron sputter epitaxy
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-209664 (URN)10.1016/j.surfcoat.2024.131534 (DOI)001353994700001 ()2-s2.0-85208189228 (Scopus ID)
Note

Funding: The authors acknowledge financial support from Swedish National Graduate School in Neutron Scattering (SwedNess), Swedish Foundation for Strategic Research (SSF) GSn15 - 0008, Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials (AFM) at Linköping University (Faculty Grant SFO Mat LiU No. 2009 00971), S.D. acknowledges student grants from Center in Nanoscience and technology at LiTH CeNano 2021 and 2022, scholarships from Society of Vacuum Coaters Foundation (SVCF) 2023, and Hans Werthén Foundation (IVA) 2023. Swedish Research Council (VR) Grant numbers 2019-00191 (for accelerator-based ion-technological center in tandem accelerator laboratory in Uppsala University), VR and SSF for access to ARTEMI, the Swedish National Infrastructure in Advanced Electron Microscopy (2021-00171 and RIF21-0026), Knut and Alice Wallenberg Foundation for the support of the electron microscopy laboratory at Linköping University (KAW 2015.0043).

Available from: 2024-11-14 Created: 2024-11-14 Last updated: 2025-02-28Bibliographically approved
Eriksson, F., Ghafoor, N., Broekhuijsen, S., Greczynski, G., Schell, N. & Birch, J. (2023). Morphology control in Ni/Ti multilayer neutron mirrors by ion-assisted interface engineering and B4C incorporation. Optical Materials Express, 13(5), 1424-1439
Open this publication in new window or tab >>Morphology control in Ni/Ti multilayer neutron mirrors by ion-assisted interface engineering and B4C incorporation
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2023 (English)In: Optical Materials Express, E-ISSN 2159-3930, Vol. 13, no 5, p. 1424-1439Article in journal (Refereed) Published
Abstract [en]

The optical contrast and minimum layer thickness of Ni/Ti broadband neutron multilayer supermirrors is usually hampered by an interface width, typically 0.7 nm, caused by nanocrystallites, interdiffusion, and/or intermixing. We explore the elimination of nanocrystallites in combination with interface smoothening by modulation of ion assistance during magnetron sputter deposition of 0.8 to 6.4 nm thick Ni and Ti layers. The amorphization is achieved through incorporation of natural B4C where B and C preferably bond to Ti. A two-stage substrate bias was applied to each layer; -30 V for the initial 1 nm followed by -100 V for the remaining part, generating multilayer mirrors with interface widths of 0.40-0.45 nm. The results predict that high performance supermirrors with m-values as high as 10 are feasible by using 11B isotope-enriched B4C combined with temporal control of the ion assistance.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
Keywords
Ion beam analysis; Ion beams; Magnetic fields; Optical components; X ray diffraction; X ray mirrors
National Category
Subatomic Physics
Identifiers
urn:nbn:se:liu:diva-193550 (URN)10.1364/OME.476713 (DOI)000994009100005 ()
Note

Funding: Stiftelsen för Strategisk Forskning; Vetenskapsrådet.

Available from: 2023-05-05 Created: 2023-05-05 Last updated: 2025-02-14Bibliographically approved
Broekhuijsen, S., Ghafoor, N., Vorobiev, A., Birch, J. & Eriksson, F. (2023). Synthesis and characterization of 11B4C containing Ni/Ti multilayers using combined neutron and X-ray reflectometry. Optical Materials Express, 13(4), 1140-1149
Open this publication in new window or tab >>Synthesis and characterization of 11B4C containing Ni/Ti multilayers using combined neutron and X-ray reflectometry
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2023 (English)In: Optical Materials Express, E-ISSN 2159-3930, Vol. 13, no 4, p. 1140-1149Article in journal (Refereed) Published
Abstract [en]

The performance of multilayers in optical components, such as those used in neutron scattering instruments, is crucially dependent on the achievable interface width. We have shown how the interface width of Ni/Ti multilayers can be improved using the incorporation of B4C to inhibit the formation of nanocrystals and limit interdiffusion and intermetallic reactions at the interfaces. A modulated ion-assistance scheme was used to prevent intermixing and roughness accumulation throughout the layer stack. In this work we investigate the incorporation of low-neutron-absorbing 11B4C for Ni/Ti neutron multilayers. Combined fitting of neutron reflectivity and X-ray reflectivity measurements shows an elimination of accumulated roughness for the 11B4C containing multilayers with a mean interface width of 4.5 Å, resulting in an increase in reflectivity at the first Bragg peak by a factor of 2.3 and 1.5 for neutron and X-ray measurements, respectively.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
Keywords
Condensed matter; Ion beam analysis; Optical components; Reflectivity; Synchrotron radiation; X ray mirrors
National Category
Subatomic Physics
Identifiers
urn:nbn:se:liu:diva-193551 (URN)10.1364/OME.481049 (DOI)000971519500001 ()
Available from: 2023-05-05 Created: 2023-05-05 Last updated: 2025-02-14Bibliographically approved
Chang, J.-C., Birch, J., Kostov Gueorguiev, G., Bakhit, B., Greczynski, G., Eriksson, F., . . . Hsiao, C.-L. (2022). Domain epitaxial growth of Ta3N5 film on c-plane sapphire substrate. Surface & Coatings Technology, 443, Article ID 128581.
Open this publication in new window or tab >>Domain epitaxial growth of Ta3N5 film on c-plane sapphire substrate
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2022 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 443, article id 128581Article in journal (Refereed) Published
Abstract [en]

Tritantalum pentanitride (Ta3N5) semiconductor is a promising material for photoelectrolysis of water with high efficiency. Ta3N5 is a metastable phase in the complex system of TaN binary compounds. Growing stabilized single-crystal Ta3N5 films is correspondingly challenging. Here, we demonstrate the growth of a nearly single-crystal Ta3N5 film with epitaxial domains on c-plane sapphire substrate, Al2O3(0001), by magnetron sputter epitaxy. Introduction of a small amount ~2% of O2 into the reactive sputtering gas mixed with N2 and Ar facilitates the formation of a Ta3N5 phase in the film dominated by metallic TaN. In addition, we indicate that a single-phase polycrystalline Ta3N5 film can be obtained with the assistance of a Ta2O5 seed layer. With controlling thickness of the seed layer smaller than 10 nm and annealing at 1000 °C, a crystalline β phase Ta2O5 was formed, which promotes the domain epitaxial growth of Ta3N5 films on Al2O3(0001). The mechanism behind the stabilization of the orthorhombic Ta3N5 structure resides in its stacking with the ultrathin seed layer of orthorhombic β-Ta2O5, which is energetically beneficial and reduces the lattice mismatch with the substrate.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Ta3N5, Sputtering, MSE, XRD, XPS, Water splitting, Single crystal
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-188556 (URN)10.1016/j.surfcoat.2022.128581 (DOI)000868328000003 ()
Note

Funding: Swedish Research Council [2018-04198, 2021-00357]; Swedish Energy Agency [46658-1]; Stiftelsen Olle Engkvist Byggmastare [197-0210]; Linkoping University Library; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]

Available from: 2022-09-16 Created: 2022-09-16 Last updated: 2023-12-21Bibliographically approved
Ekström, E., Elsukova, A., Grasland, J., Palisaitis, J., Ramanath, G., Persson, P., . . . Eklund, P. (2022). Epitaxial Growth of CaMnO3-y Films on LaAlO3 (112 over bar 0) by Pulsed Direct Current Reactive Magnetron Sputtering. Physica Status Solidi. Rapid Research Letters, 16(4), Article ID 2100504.
Open this publication in new window or tab >>Epitaxial Growth of CaMnO3-y Films on LaAlO3 (112 over bar 0) by Pulsed Direct Current Reactive Magnetron Sputtering
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2022 (English)In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 16, no 4, article id 2100504Article in journal (Refereed) Published
Abstract [en]

CaMnO3 is a perovskite with attractive magnetic and thermoelectric properties. CaMnO3 films are usually grown by pulsed laser deposition or radio frequency magnetron sputtering from ceramic targets. Herein, epitaxial growth of CaMnO3-y (002) films on a (112 over bar 0)-oriented LaAlO3 substrate using pulsed direct current reactive magnetron sputtering is demonstrated, which is more suitable for industrial scale depositions. The CaMnO3-y shows growth with a small in-plane tilt of <approximate to 0.2 degrees toward the (200) plane of CaMnO3-y and the (1 over bar 104) with respect to the LaAlO3 (112 over bar 0) substrate. X-ray photoelectron spectroscopy of the electronic core levels shows an oxygen deficiency described by CaMnO2.58 that yields a lower Seebeck coefficient and a higher electrical resistivity when compared to stoichiometric CaMnO3. The LaAlO3 (112 over bar 0) substrate promotes tensile-strained growth of single crystals. Scanning transmission electron microscopy and electron energy loss spectroscopy reveal antiphase boundaries composed of Ca on Mn sites along and , forming stacking faults.

Place, publisher, year, edition, pages
Wiley-V C H Verlag GMBH, 2022
Keywords
CaMnO3; epitaxy; perovskites; PVD
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-182501 (URN)10.1002/pssr.202100504 (DOI)000741329200001 ()
Note

Funding Agencies|Swedish Research Council (VR)Swedish Research Council [2016-03365]; Knut and Alice Wallenberg Foundation through the Wallenberg Academy Fellows program [KAW 2020.0196]; Electron Microscopy Laboratory at Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Swedish Energy AgencySwedish Energy AgencyMaterials & Energy Research Center (MERC) [46519-1]; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research [RIF 14-0074]

Available from: 2022-01-26 Created: 2022-01-26 Last updated: 2023-05-09Bibliographically approved
Gharavi, M. A., Gambino, D., Le Febvrier, A., Eriksson, F., Armiento, R., Alling, B. & Eklund, P. (2021). High thermoelectric power factor of pure and vanadium-alloyed chromium nitride thin films. Materials Today Communications, 28, Article ID 102493.
Open this publication in new window or tab >>High thermoelectric power factor of pure and vanadium-alloyed chromium nitride thin films
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2021 (English)In: Materials Today Communications, ISSN 2352-4928, Vol. 28, article id 102493Article in journal (Refereed) Published
Abstract [en]

Chromium-nitride based materials have shown unexpected promise as thermo-electric materials for, e.g., wasteheat harvesting. Here, CrN and (Cr,V)N thin films were deposited by reactive magnetron sputtering. Thermoelectric measurements of pure CrN thin films show a low electrical resistivity between 1.2 and 1.5 x 10(-3) Omega cm and very high values of the Seebeck coefficient and thermoelectric power factor, in the range between 370-430 mu V/K and 9-11 x 10(-3) W/mK(2), respectively. Alloying of CrN films with small amounts (less than 15 %) of vanadium results in cubic (Cr,V)N thin films. Vanadium decreases the electrical resistivity and yields powerfactor values in the same range as pure CrN. Density functional theory calculations of sub-stoichiometric CrN1-delta and (Cr,V)N1-delta show that nitrogen vacancies and vanadium substitution both cause n-type conductivity and features in the band structure typically correlated with a high Seebeck coefficient. The results suggest that slight variations in nitrogen and vanadium content affect the power factor and offers a means of tailoring the power factor and thermoelectric figure of merit.

Place, publisher, year, edition, pages
ELSEVIER, 2021
Keywords
Transition-metal nitrides; Sputter deposition; Thermoelectrics; Density functional theory; Energy harvesting
National Category
Materials Engineering Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-178234 (URN)10.1016/j.mtcomm.2021.102493 (DOI)000707388200007 ()
Note

Funding: Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Swedish Research Council (VR)Swedish Research Council [2019-05403, 2016-03365]; Swedish Foundation for Strategic Research through the Future Research Leaders 6 program [FFL 15-0290]; Knut and Alice Wallenberg Foundation (Wallenberg Scholar Grant) [KAW2018.0194]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2018-05973]

Available from: 2021-08-18 Created: 2021-08-18 Last updated: 2022-04-05
Chang, J.-C., Eriksson, F., Sortica, M. A., Greczynski, G., Bakhit, B., Hu, Z.-J., . . . Hsiao, C.-L. (2021). Orthorhombic Ta3-xN5-yOy thin films grown by unbalanced magnetron sputtering: The role of oxygen on structure, composition, and optical properties. Surface & Coatings Technology, 406, Article ID 126665.
Open this publication in new window or tab >>Orthorhombic Ta3-xN5-yOy thin films grown by unbalanced magnetron sputtering: The role of oxygen on structure, composition, and optical properties
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2021 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 406, article id 126665Article in journal (Refereed) Published
Abstract [en]

Direct growth of orthorhombic Ta3N5-type Ta-O-N compound thin films, specifically Ta3-xN5-yOy, on Si and sapphire substrates with various atomic fractions is realized by unbalanced magnetron sputtering. Low-degree fiber-textural Ta3-xN5-yOy films were grown through reactive sputtering of Ta in a gas mixture of N-2, Ar, and O-2 with keeping a partial pressure ratio of 3:2:0.1 in a total working pressure range of 5-30 mTorr. With increasing total pressure from 5 to 30 mTorr, the atomic fraction of O in the as-grown Ta3-xN5-yOy films was found to increase from 0.02 to 0.15 while that of N and Ta decrease from 0.66 to 0.54 and 0.33 to 0.31, respectively, leading to a decrease in b lattice constant up to around 1.3%. Metallic TaNx phases were formed without oxygen. For a working pressure of 40 mTorr, an amorphous, O-rich Ta-N-O compound film with a high O fraction of similar to 0.48, was formed, mixed with non-stoichiometric TaON and Ta2O5. By analyzing the plasma discharge, the increasing O incorporation is associated with oxide formation on top of the Ta target due to a higher reactivity of Ta with O than with N. The increase of O incorporation in the films also leads to a optical bandgap widening from similar to 2.22 to similar to 2.96 eV, which is in agreement with the compositional and structural changes from a crystalline Ta3-xN5-yOy to an amorphous O-rich Ta-O-N compound.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2021
Keywords
Ta3N5; Magnetron sputtering; XRD; XPS; ERDA; Optical absorption spectroscopy
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-173006 (URN)10.1016/j.surfcoat.2020.126665 (DOI)000604750600025 ()
Note

Funding Agencies|Vetenskapseddet [2018-04198]; Energimyndigheten [46658-1]; Stiftelsen 011e Engkvist Byggmastare [197-0210]; Linkoping University Library; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; VR-RFI [821-2012-5144, 2017-00646_9]; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research [RIF14-0053, 5E13-0333]

Available from: 2021-01-27 Created: 2021-01-27 Last updated: 2023-12-21
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