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Schroeder, Jeremy L.
Alternative names
Publications (9 of 9) Show all publications
Saha, B., Rui Koh, Y., Comparan, J., Sadasivam, S., Schroeder, J., Garbrecht, M., . . . Sands, T. D. (2016). Cross-plane thermal conductivity of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices. Physical Review B, 93(4), 045311
Open this publication in new window or tab >>Cross-plane thermal conductivity of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices
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2016 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 93, no 4, p. 045311-Article in journal (Refereed) Published
Abstract [en]

Reduction of cross-plane thermal conductivity and understanding of the mechanisms of heat transport in nanostructured metal/semiconductor superlattices are crucial for their potential applications in thermoelectric and thermionic energy conversion devices, thermal management systems, and thermal barrier coatings. We have developed epitaxial (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices with periodicity ranging from 1 nm to 240 nm that show significantly lower thermal conductivity compared to the parent TiN/(Al, Sc) N superlattice system. The (Ti,W)N/(Al,Sc)N superlattices grow with [001] orientation on the MgO(001) substrates with well-defined coherent layers and are nominally single crystalline with low densities of extended defects. Cross-plane thermal conductivity (measured by time-domain thermoreflectance) decreases with an increase in the superlattice interface density in a manner that is consistent with incoherent phonon boundary scattering. Thermal conductivity values saturate at 1.7W m(-1) K-1 for short superlattice periods possibly due to a delicate balance between long-wavelength coherent phonon modes and incoherent phonon scattering from heavy tungsten atomic sites and superlattice interfaces. First-principles density functional perturbation theory based calculations are performed to model the vibrational spectrum of the individual component materials, and transport models are used to explain the interface thermal conductance across the (Ti,W)N/(Al,Sc)N interfaces as a function of periodicity. The long-wavelength coherent phonon modes are expected to play a dominant role in the thermal transport properties of the short-period superlattices. Our analysis of the thermal transport properties of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices addresses fundamental questions about heat transport in multilayer materials.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-125146 (URN)10.1103/PhysRevB.93.045311 (DOI)000368487500010 ()
Note

Funding Agencies|National Science Foundation; U.S. Department of Energy [CBET-1048616]; Defense Advanced Research Projects Agency (DARPA)/Army Research Office [W911NF0810347]; Louis Stokes Alliance for Minority Participation (LSAMP) program; Office of Naval Research [N000141211006]; Swedish Research Council [RAC Frame Program] [2011-6505]; Swedish Research Council [Linnaeus Grant (LiLi-NFM)]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]

Available from: 2016-02-15 Created: 2016-02-15 Last updated: 2017-11-30
Garbrecht, M., Schroeder, J., Hultman, L., Birch, J., Saha, B. & Sands, T. D. (2016). Microstructural evolution and thermal stability of HfN/ScN, ZrN/ScN, and Hf0.5Zr0.5N/ScN metal/semiconductor superlattices. Journal of Materials Science, 51(17), 8250-8258
Open this publication in new window or tab >>Microstructural evolution and thermal stability of HfN/ScN, ZrN/ScN, and Hf0.5Zr0.5N/ScN metal/semiconductor superlattices
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2016 (English)In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 51, no 17, p. 8250-8258Article in journal (Refereed) Published
Abstract [en]

Nitride-based metal/semiconductor superlattices for possible applications as thermoelectric, plasmonic, and hard coating materials have been grown by magnetron sputtering. Since long-time thermal stability of the superlattices is crucial for these applications, the atomic scale microstructure and its evolution under annealing to working temperatures were investigated with high-resolution transmission electron microscopy methods. We report on epitaxial growth of three cubic superlattice systems (HfN/ScN, ZrN/ScN, and Hf0.5Zr0.5N/ScN) that show long-time thermal stability (annealing up to 120 h at 950 degrees C) as monitored by scanning transmission electron microscopy-based energy-dispersive X-ray spectroscopy. No interdiffusion between the metal and semiconductor layers could be observed for any of the present systems under long-time annealing, which is in contrast to earlier attempts on similar superlattice structures based on TiN as the metallic compound. Atomically resolved high-resolution transmission electron microscopy imaging revealed that even though the superlattice curves towards the substrate at regular interval column boundaries originating from threading dislocations close to the substrate interface, the cubic lattice continues coherently across the boundaries. It is found that the boundaries themselves are alloyed along the entire growth direction, while in their vicinity nanometer-size inclusions of metallic phases are observed that could be identified as the zinc blende phase of same stoichiometry as the parent rock salt transition metal nitride phase. Our results demonstrate the longtime thermal stability of metal/semiconductor superlattices based on Zr and Hf nitrides.

Place, publisher, year, edition, pages
SPRINGER, 2016
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-130255 (URN)10.1007/s10853-016-0102-6 (DOI)000378542500038 ()
Note

Funding Agencies|Swedish Research Council [2011-6505, 2013-4018]; Swedish Government [SFO-Mat-LiU 2009-00971]; National Science Foundation; U.S. Department of Energy [CBET-1048616]

Available from: 2016-08-01 Created: 2016-07-28 Last updated: 2017-11-28
Schroeder, J., Ingason, A. S., Rosén, J. & Birch, J. (2015). Beware of poor-quality MgO substrates: A study of MgO substrate quality and its effect on thin film quality. Journal of Crystal Growth, 420, 22-31
Open this publication in new window or tab >>Beware of poor-quality MgO substrates: A study of MgO substrate quality and its effect on thin film quality
2015 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 420, p. 22-31Article in journal (Refereed) Published
Abstract [en]

Magnesium oxide (MgO) substrates are widely used for fundamental research of a large variety of materials. Our motivation is to make the research community aware of poor-quality MgO substrates. We acquired thirty MgO substrates from six different vendors and demonstrate that single-crystal MgO substrates are not always single crystal, but can consist of multiple domains. These multiple-domain MgO substrates can have a significant impact on research results as demonstrated by a one-to-one correlation between the domain structure of MgO substrates and titanium nitride (TiN) thin films (i.e. poor-quality MgO substrates result in poor-quality TiN films). Poor-quality MgO substrates are shown to be a widespread problem with over 70% of the evaluated substrates exhibiting multiple domains, essentially disqualifying them as substrates for epitaxy. MgO substrate vendors and researchers are encouraged to work together to resolve the problem of inconsistent MgO substrate quality and the research community is encouraged to perform quality control of MgO substrates prior to thin film deposition. Quality control by vendors and/or researchers can be achieved by acquiring X-ray diffraction omega-phi maps in batch processes, as detailed in this paper. We also propose a simple quality grading system to differentiate MgO substrates of varying quality.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Characterization; Crystal morphology; High resolution X-ray diffraction; Substrates; Solid phase epitaxy; Magnesium oxide
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-118838 (URN)10.1016/j.jcrysgro.2015.03.010 (DOI)000353825100005 ()
Note

Funding Agencies|Linkoping University; Swedish Research Council (the RAC Frame Program) [2011-6505]; Linnaeus Grant (LiLi-NFM); European Research Council under the European Community Seventh Framework Program/ERC Grant [258509]; Knut and Alice Wallenberg (KAW) Fellowship program

Available from: 2015-06-08 Created: 2015-06-04 Last updated: 2017-12-04
Schroeder, J., Thomson, W., Howard, B., Schell, N., Näslund, L.-Å., Rogström, L., . . . Birch, J. (2015). Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation. Review of Scientific Instruments, 86(9), 095113
Open this publication in new window or tab >>Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation
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2015 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 86, no 9, p. 095113-Article in journal (Refereed) Published
Abstract [en]

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (greater than50 keV), high photon flux (greater than10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (less than1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (less than11 degrees), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument. (C) 2015 AIP Publishing LLC.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2015
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-122441 (URN)10.1063/1.4930243 (DOI)000362573300065 ()26429486 (PubMedID)
Note

Funding Agencies|Swedish Research Council via the Rontgen Angstrom Cluster (RAC) Frame Program [2011-6505]; German Federal Ministry of Education and Research (BMBF) [05K12CG1]

Available from: 2015-11-03 Created: 2015-11-02 Last updated: 2019-10-07
Paul, B., Schroeder, J. L., Kerdsongpanya, S., van Nong, N., Schell, N., Ostach, D., . . . Eklund, P. (2015). Mechanism of Formation of the Thermoelectric Layered Cobaltate Ca3Co4O9 by Annealing of CaO-CoO Thin Films. Advanced Electronic Materials, 1(3), Article ID 1400022.
Open this publication in new window or tab >>Mechanism of Formation of the Thermoelectric Layered Cobaltate Ca3Co4O9 by Annealing of CaO-CoO Thin Films
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2015 (English)In: Advanced Electronic Materials, ISSN 2199-160X, Vol. 1, no 3, article id 1400022Article in journal (Refereed) Published
Abstract [en]

The layered cobaltate Ca3Co4O9 is of interest for energy-harvesting and heat-conversion applications because of its good thermoelectric properties and the fact that the raw materials Ca and Co are nontoxic, abundantly available, and inexpensive. While single-crystalline Ca3Co4O9 exhibits high Seebeck coefficient and low resistivity, its widespread use is hampered by the fact that single crystals are too small and expensive. A promising alternative approach is the growth of highly textured and/or epitaxial Ca3Co4O9 thin films with correspondingly anisotropic properties. Here, we present a two-step sputtering/annealing method for the formation of highly textured virtually phase-pure Ca3Co4O9 thin films by reactive cosputtering from Ca and Co targets followed by an annealing process at 730 °C under O2-gas flow. The thermally induced phase transformation mechanism is investigated by in situ time-resolved annealing experiments using synchrotron-based 2D X-ray diffraction (XRD) as well as ex situ annealing experiments and standard lab-based XRD. By tuning the proportion of initial CaO and CoO phases during film deposition, the method enables synthesis of Ca3Co4O9 thin films as well as CaxCoO2. With this method, we demonstrate production of epitaxial Ca3Co4O9 thin films with in-plane electrical resistivity of 6.44 mΩ cm and a Seebeck coefficient of 118 μV K−1 at 300 K.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2015
Keywords
Thermoelectrics, Ca3Co4O9, thin film, sputtering, phase transformation
National Category
Condensed Matter Physics Other Materials Engineering Nano Technology
Identifiers
urn:nbn:se:liu:diva-117610 (URN)10.1002/aelm.201400022 (DOI)000357653900004 ()
Funder
EU, European Research Council, 335383Swedish Research Council, 2012-4430Swedish Research Council, 2011-6505Swedish Foundation for Strategic Research , Future Research Leaders 5
Available from: 2015-05-06 Created: 2015-05-06 Last updated: 2016-02-16Bibliographically approved
Schroeder, J., Saha, B., Garbrecht, M., Schell, N., Sands, T. D. & Birch, J. (2015). Thermal stability of epitaxial cubic-TiN/(Al,Sc)N metal/semiconductor superlattices. Journal of Materials Science, 50(8), 3200-3206
Open this publication in new window or tab >>Thermal stability of epitaxial cubic-TiN/(Al,Sc)N metal/semiconductor superlattices
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2015 (English)In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 50, no 8, p. 3200-3206Article in journal (Refereed) Published
Abstract [en]

We report on the thermal stability of epitaxial cubic-TiN/(Al,Sc)N metal/semiconductor superlattices with the rocksalt crystal structure for potential plasmonic, thermoelectric, and hard coating applications. TiN/Al0.72Sc0.28N superlattices were annealed at 950 and 1050 A degrees C for 4, 24, and 120 h, and the thermal stability was characterized by high-energy synchrotron-radiation-based 2D X-ray diffraction, high-resolution (scanning) transmission electron microscopy [HR(S)/TEM], and energy dispersive X-ray spectroscopy (EDX) mapping. The TiN/Al0.72Sc0.28N superlattices were nominally stable for up to 4 h at both 950 and 1050 A degrees C. Further annealing treatments for 24 and 120 h at 950 A degrees C led to severe interdiffusion between the layers and the metastable cubic-Al0.72Sc0.28N layers partially transformed into Al-deficient cubic-(Al,Sc)N and the thermodynamically stable hexagonal wurtzite phase with a nominal composition of AlN (h-AlN). The h-AlN grains displayed two epitaxial variants with respect to c-TiN and cubic-(Al,Sc)N. EDX mapping suggests that scandium has a higher tendency for diffusion in TiN/(Al,Sc)N than titanium or aluminum. Our results indicate that the kinetics of interdiffusion and the cubic-to-hexagonal phase transformation place constraints on the design and implementation of TiN/(Al,Sc)N superlattices for high-temperature applications.

Place, publisher, year, edition, pages
Springer Verlag (Germany), 2015
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-116502 (URN)10.1007/s10853-015-8884-5 (DOI)000349969800021 ()
Note

Funding Agencies|Linkoping University; Swedish Research Council [2011-6505]; National Science Foundation; US Department of Energy [CBET-1048616]

Available from: 2015-03-27 Created: 2015-03-27 Last updated: 2017-12-04
Rogström, L., Ghafoor, N., Schroeder, J., Schell, N., Birch, J., Ahlgren, M. & Odén, M. (2015). Thermal stability of wurtzite Zr1-xAlxN coatings studied by in situ high-energy x-ray diffraction during annealing. Journal of Applied Physics, 118(3), Article ID 035309.
Open this publication in new window or tab >>Thermal stability of wurtzite Zr1-xAlxN coatings studied by in situ high-energy x-ray diffraction during annealing
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2015 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, no 3, article id 035309Article in journal (Refereed) Published
Abstract [en]

We study the thermal stability of wurtzite (w) structure ZrAlN coatings by a combination of in situ high-energy x-ray scattering techniques during annealing and electron microscopy. Wurtzite structure Zr1-xAlxN coatings with Al-contents from x = 0.46 to x = 0.71 were grown by cathodic arc evaporation. The stability of the w-ZrAlN phase depends on chemical composition where the higher Al-content coatings are more stable. The wurtzite ZrAlN phase was found to phase separate through spinodal decomposition, resulting in nanoscale compositional modulations, i.e., alternating Al-rich ZrAlN layers and Zr-rich ZrAlN layers, forming within the hexagonal lattice. The period of the compositional modulations varies between 1.7 and 2.5 nm and depends on the chemical composition of the coating where smaller periods form in the more unstable, high Zr-content coatings. In addition, Zr leaves the w-ZrAlN lattice to form cubic ZrN precipitates in the column boundaries. (C) 2015 AIP Publishing LLC.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2015
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-120742 (URN)10.1063/1.4927156 (DOI)000358429200055 ()
Note

Funding Agencies|VINN Excellence Center on Functional Nanoscale Materials (FunMat); Rontgen-Angstrom Cluster [VR 2011-6505]

Available from: 2015-08-24 Created: 2015-08-24 Last updated: 2017-12-04
Schroeder, J. L., Ewoldt, D. A., Amatya, R., Ram, R. J., Shakouri, A. & Sands, T. D. (2014). Bulk-Like Laminated Nitride Metal/Semiconductor Superlattices for Thermoelectric Devices. Journal of microelectromechanical systems, 23(3), 672-680
Open this publication in new window or tab >>Bulk-Like Laminated Nitride Metal/Semiconductor Superlattices for Thermoelectric Devices
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2014 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 23, no 3, p. 672-680Article in journal (Refereed) Published
Abstract [en]

Bulk-like thermionic energy conversion devices have been fabricated from nanostructured nitride metal/semiconductor superlattices using a novel lamination process. 5-mu m thick (Hf0.5Zr0.5)N (6-nm)/ScN (6-nm) metal/semiconductor superlattices with a 12 nm period were deposited on 100-silicon substrates by reactive magnetron sputtering followed by a selective tetra methyl ammonium hydroxide substrate etching and a gold-gold lamination process to yield 300 mu m x 300 mu m x 290 mu m microscale thermionic energy conversion elements with 16,640 superlattice periods. The thermionic element had a Seebeck coefficient of -120 mu V/K at 800 K, an electrical conductivity of similar to 2500 Omega(-1)m(-1) at 800 K, and a thermal conductivity of 2.9 and 4.3 W/m-K at 300 and 625 K, respectively. The temperature dependence of the Seebeck coefficient from 300 to 800 K suggests a parallel parasitic conduction path that is dominant at low temperature, and the temperature independent electrical conductivity indicates that the (Hf0.5Zr0.5)N/gold interface contact resistivity currently dominates the device. The thermal conductivity of the laminate was significantly lower than the thermal conductivity of the individual metal or semiconductor layers, indicating the beneficial effect of the metal/semiconductor interfaces toward lowering the thermal conductivity. The described lamination process effectively bridges the gap between the nanoscale requirements needed to enhance the thermoelectric figure of merit ZT and the microscale requirements of real-world devices.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2014
Keywords
Laminates; superlattices; thermionic energy conversion; thermoelectric devices
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-108931 (URN)10.1109/JMEMS.2013.2282743 (DOI)000337128200023 ()
Available from: 2014-07-15 Created: 2014-07-13 Last updated: 2017-12-05
Saha, B., Lawrence, S. K., Schroeder, J., Birch, J., Bahr, D. F. & Sands, T. D. (2014). Enhanced hardness in epitaxial TiAlScN alloy thin films and rocksalt TiN/(Al,Sc)N superlattices. Applied Physics Letters, 105(15), 151904
Open this publication in new window or tab >>Enhanced hardness in epitaxial TiAlScN alloy thin films and rocksalt TiN/(Al,Sc)N superlattices
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2014 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, no 15, p. 151904-Article in journal (Refereed) Published
Abstract [en]

High hardness TiAlN alloys for wear-resistant coatings exhibit limited lifetimes at elevated temperatures due to a cubic-AlN to hexagonal-AlN phase transformation that leads to decreasing hardness. We enhance the hardness (up to 46 GPa) and maximum operating temperature (up to 1050 degrees C) of TiAlN-based coatings by alloying with scandium nitride to form both an epitaxial TiAlScN alloy film and epitaxial rocksalt TiN/(Al,Sc)N superlattices on MgO substrates. The superlattice hardness increases with decreasing period thickness, which is understood by the Orowan bowing mechanism of the confined layer slip model. These results make them worthy of additional research for industrial coating applications.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2014
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-112480 (URN)10.1063/1.4898067 (DOI)000344344700024 ()
Note

Funding Agencies|National Science Foundation; U.S. Department of Energy [CBET-1048616]; Department of Energy National Nuclear Security Administration [DE-FC52-08NA28752]; Linkoping University; Swedish Research Council (the RAC Frame Program) [2011-6505]; Swedish Research Council (Linnaeus Grant) [LiLi-NFM]

Available from: 2014-11-28 Created: 2014-11-28 Last updated: 2017-12-05
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