Materials Scientist
Physical Metallurgy Materials Group
Materials Scientist
Physical Metallurgy Materials Group

Biography

Dr. Kaspar joined PNNL as a graduate student in 2000. After graduation, she remained as a post-doctoral researcher, and was hired as a full-time staff scientist in PCSD in 2007.

Dr. Kaspar has over 20 years of experience with epitaxial oxide deposition by oxygen-plasma-assisted molecular beam epitaxy and pulsed laser deposition in the Oxide Epitaxy Laboratory at PNNL. Her expertise centers on systematic structural characterization of epitaxial films with scattering, spectroscopic, and imaging techniques. This information is then combined with the evaluation of electronic, magnetic, photocatalytic, and/or piezoelectric properties to establish structure-property relationships that provide insight into the physics underlying observed phenomena. The mechanisms of dynamic phenomena such as mass transport under external stimuli (temperature, radiation) is investigated at the atomic scale. The role of intentional and unintentional defects (e.g., dopants, cation and anion non-stoichiometry, misfit dislocations) on oxide structure and properties is a running theme through Dr. Kaspar’s work. 

The advent of artificial intelligence (AI) and machine learning (ML) algorithms to enhance scientific data analysis have opened up unprecedented opportunities to revolutionize materials science. Dr. Kaspar is capitalizing on this opportunity as part of PNNL’s AT SCALE Initiative. Her project is developing AI/ML approaches to analyze, in real time, reflection high energy electron diffraction (RHEED) data collected during epitaxial film deposition and use this information to execute intelligent feedback control decisions. Real-time feedback control to guide synthesis is a critical component of autonomous experimentation, which promises a paradigm shift in the speed of materials discovery and synthesis.  

Other research projects have included tuning the magnetic properties of transition-metal-doped TiO2 and ZnO as potential dilute magnetic semiconductors and investigating the electronic, photoactive, and magnetic properties of doped binary and complex oxides. Particular emphasis is placed on the relationship between the electronic changes that occur with doping and the resulting photoabsorption and carrier generation processes. Additional recent research areas have included the synthesis of lattice-mismatched epitaxial metal films on oxide substrates for radiation damage studies, the development of new complex oxides as high temperature, radiation-resistant piezoelectrics for use in advanced in situ sensors, and fundamental investigations into radiation-enhanced cation and anion diffusion mechanisms using isotopic tracers incorporated into epitaxial oxide thin films.  

Research Interests

· Epitaxial growth and structural characterization of metallic and metal oxide films

· Real-time AI/ML analysis of data from in situ analytical tools to enable autonomous experimentation with on-the-fly feedback control of film deposition

· Magnetic and electronic properties of doped metal oxide films

· Electronic and photochemical characterization of materials relevant for energy applications

· Cation and anion transport in oxides, semiconductors, and metals under extreme conditions

Education and Credentials

· University of Colorado, Boulder, CO, B.S.Chemical Engineering, (1998)

· University of Washington, Seattle, WA, Ph.D. Chemical Engineering, (2004)

Education

  • Doctor of Philosophy in Chemical Engineering, University of Washington
  • Bachelor of Science in Chemical Engineering, University of Colorado at Boulder

Affiliations and Professional Service

  • American Vacuum Society (AVS) (1999-present)
  • American Ceramic Society (ACerS) (2017-present)
  • Associate Editor, Surface Analysis section of Frontiers Analytical Science
  • Guest Editor of JVSTA special issue on “AI and ML for Materials Discovery, Synthesis and Characterization” (2024)
  • American Ceramic Society Electronic Materials and Applications (EMA) conference Session S10, Point Defects and Transport in Ceramics, organizing committee (2021-present)
  • AVS Magnetic Interfaces and Nanostructures Division Executive Committee (2019-2024)
  • International Conference on Molecular Beam Epitaxy, Oxides Subcommittee member (2022)
  • APS March Meeting organizer for Focus Topic 10.1.3, Magnetic Oxide Thin Films and Heterostructures (2019, 2020)
  • Environmental Molecular Sciences Laboratory (EMSL) User Executive Committee elected member (2015-2018)
  • Pacific Northwest Chapter of AVS (PNWAVS): Central WA Representative (2009–2011); Chair (2012); Secretary (2013¬–present); Co-Chair of joint PNWAVS/Surface Analysis Symposium (2012, 2022)
  • Argonne National Laboratory's Center for Nanoscale Materials Proposal Review Board

Awards and Recognitions

Publications

2026

  • Kretov, D., T. Kaspar, B. Derby, D. Schreiber, and D. Kaoumi. 2026. Irradiation-Induced Grain Growth of γFe2O3 and Fe3O4at Cryogenic Temperatures. Scripta Materialia 275, 117179. doi:10.1016/j.scriptamat.2026.117179
  • Christudasjustus, J., K. Yano, M. Choi, M. Bowden, T. Ajantiwalay, V. Shutthanandan, D. Edwards, P. Hosemann, D. Schreiber, and T. Kaspar. 2026. Dose-dependent evolution of dislocation structures and bubble formation in He irradiated Fe-Cr epitaxial film. Materialia, 102657. doi:10.1016/j.mtla.2026.102657

2025

  • , ., O. Bel, . , S. Kim, K. Agarwal, D. Barajas-Solano, T. Kaspar, R. Mars, S. Choudhury, G. Seppala, and A. Amante. 2025. VISIONARY: Virtual Intelligence System for Optimizing Novel Analytical Research Yields. doi:10.2172/2998424
  • 2025. On the Structure–Property Relationship of Semi‐Coherent FeCr2O4/Cr2O3 Spinel/Corundum Interfaces. Advanced Materials Interfaces. doi:10.1002/admi.202500047
  • 2025. Machine-learning-enabled on-the-fly analysis of RHEED patterns during thin film deposition by molecular beam epitaxy. Journal of Vacuum Science & Technology A. doi:10.1116/6.0004493
  • Kaspar, T., M. Liedke, K. Yano, J. Christudasjustus, H. Kim, Y. Wang, M. Bowden, G. Sterbinsky, M. Butterling, E. Hirschmann, A. Wagner, and D. Schreiber. 2025. Defect Generation and Evolution in Irradiated Epitaxial Films and Heterostructures of Fe3O4 and Cr2O3. Advanced Materials Interfaces. doi:10.1002/admi.202400893

2024

  • , ., S. Jana, . , A. Lall, T. Kaspar, S. Riechers, R. Meyer, Z. Kennedy, M. Fenn, and K. Ross. 2024. Embedded Aluminum Nitride Sensors for Advanced Reactors. doi:10.2172/3000486
  • 2024. Synthesis, Processing, and Use of Isotopically Enriched Epitaxial Oxide Thin Films. Accounts of Materials Research. doi:10.1021/accountsmr.3c00148
  • 2024. Directly resolving surface vs. lattice self-diffusion in iron at the nanoscale using in situ atom probe capabilities. Materialia. doi:10.1016/j.mtla.2024.102078

2023

  • Kaspar, T., S. Spurgeon, K. Yano, B. Matthews, M. Bowden, C. Ophus, H. Kim, Y. Wang, and D. Schreiber. 2023. Role of structural defects in mediating disordering processes at irradiated epitaxial Fe3O4/Cr2O3 interfaces. Physical Review Materials 7(9). doi:10.1103/PhysRevMaterials.7.093604
  • Chrysler, M., J. Gabel, T. Lee, Z. Zhu, T. Kaspar, M. Bowden, P. Sushko, S. Chambers, and J. Ngai. 2023. Surface termination control of charge transfer and band alignment across a semiconductor–crystalline-oxide heterojunction. Physical Review Materials 7(8). doi:10.1103/PhysRevMaterials.7.084604

2022

  • Kaspar, T., Y. Du, M. Engelhard, D. Baer, B. Jalan, and J. Ngai. 2022. Preface for the special topic collection honoring Dr. Scott Chambers’ 70th birthday and his leadership in the science and technology of oxide thin films. Journal of Vacuum Science & Technology A 40(4). doi:10.1116/6.0001942
  • Kaspar, T., P. Hatton, K. Yano, S. Taylor, S. Spurgeon, B. Uberuaga, and D. Schreiber. 2022. Adatom-Driven Oxygen Intermixing during the Deposition of Oxide Thin Films by Molecular Beam Epitaxy. Nano Letters 22(12), 4963-4969. doi:10.1021/acs.nanolett.2c01678
  • 2022. Alternate Methods for Cleaning Zirconium Plate. doi:10.2172/2344995
  • Kaspar, T., D. Li, C. Cowles, and R. Kouzes. 2022. Temperature Dependence of Optical Couplant Grease Transmission at UV and Visible Wavelengths. IEEE Transactions on Nuclear Science 69(4), 952-957. doi:10.1109/TNS.2022.3154970
  • Cowles, C., T. Kaspar, R. Kouzes, D. Li, Z. Bell, I. Ivanov, and E. Sword. 2022. Temperature-Dependent Properties of BC-412 Polyvinyl Toluene Scintillator. IEEE Transactions on Nuclear Science 69(4), 942-951. doi:10.1109/TNS.2022.3154645
  • Yano, K., A. Kohnert, T. Kaspar, S. Taylor, S. Spurgeon, H. Kim, Y. Wang, B. Uberuaga, and D. Schreiber. 2022. Dose rate dependent cation & anion radiation enhanced diffusion in hematite. Journal of Materials Chemistry A 10(45), 24167-24177. doi:10.1039/D2TA03403D

2021

  • Yano, K., A. Kohnert, T. Kaspar, S. Taylor, S. Spurgeon, H. Kim, Y. Wang, B. Uberuaga, and D. Schreiber. 2021. Radiation Enhanced Anion Diffusion in Chromia. The Journal of Physical Chemistry C 125(50), 27820-27827. doi:10.1021/acs.jpcc.1c08705
  • Wang, L., P. Adiga, J. Zhao, W. Samarakoon, K. Stoerzinger, S. Spurgeon, B. Matthews, M. Bowden, P. Sushko, T. Kaspar, G. Sterbinsky, S. Heald, H. Wang, L. Wangoh, J. Wu, E. Guo, H. Qian, J. Wang, T. Varga, S. Thevuthasan, Z. Feng, W. Yang, Y. Du, and S. Chambers. 2021. Understanding the Electronic Structure Evolution of Epitaxial LaNi1–xFexO3 Thin Films for Water Oxidation. Nano Letters 21(19), 8324-8331. doi:10.1021/acs.nanolett.1c02901
  • Efe, M., B. Gwalani, J. Tao, M. Song, T. Kaspar, A. Devaraj, and A. Rohatgi. 2021. Nanomechanical Scratching Induced Local Shear Deformation and Microstructural Evolution in Single Crystalline Copper. Applied Surface Science 562, 150132. doi:10.1016/j.apsusc.2021.150132
  • Kaspar, T., S. Spurgeon, B. Matthews, M. Bowden, S. Heald, L. Wang, R. Kelley, R. Paudel, T. Isaacs-Smith, R. Comes, X. Yin, C. Tang, A. Wee, and S. Chambers. 2021. Incorporation of Ti in epitaxial Fe2TiO4 thin films. Journal of Physics: Condensed Matter 33(31), 314004. doi:10.1088/1361-648X/ac0571
  • Matthews, B., M. Sassi, C. Barr, C. Ophus, T. Kaspar, W. Jiang, K. Hattar, and S. Spurgeon. 2021. Percolation of Ion-Irradiation-Induced Disorder in Complex Oxide Interfaces. Nano Letters 21(12), 5353-5359. doi:10.1021/acs.nanolett.1c01651
  • Kaspar, T., S. Taylor, K. Yano, T. Lach, Y. Zhou, Z. Zhu, A. Kohnert, E. Still, P. Hosemann, S. Spurgeon, and D. Schreiber. 2021. Bulk and Short‐Circuit Anion Diffusion in Epitaxial Fe2O3 Films Quantified Using Buried Isotopic Tracer Layers. Advanced Materials Interfaces 8(9). doi:10.1002/admi.202001768
  • Yano, K., A. Kohnert, A. Banerjee, D. Edwards, E. Holby, T. Kaspar, H. Kim, T. Lach, S. Taylor, Y. Wang, B. Uberuaga, and D. Schreiber. 2021. Radiation-Enhanced Anion Transport in Hematite. Chemistry of Materials 33(7), 2307-2318. doi:10.1021/acs.chemmater.0c04235
  • Blanchet, M., J. Heath, T. Kaspar, B. Matthews, S. Spurgeon, M. Bowden, S. Heald, T. Issacs-Smith, M. Kuroda, and R. Comes. 2021. Electronic and structural properties of single-crystal Jahn–Teller active Co1+x Mn2−x O4 thin films. Journal of Physics: Condensed Matter 33(12), 124002. doi:10.1088/1361-648X/abd573
  • Kaspar, T., Q. Pang, P. Sushko, M. Bowden, J. Tao, B. Gwalani, M. Olszta, M. Efe, A. Devaraj, and A. Rohatgi. 2021. Metastable orientation relationships in thin film Cu-Cr bilayers. Scripta Materialia 194, 113635. doi:10.1016/j.scriptamat.2020.113635

2020

  • Scafetta, M., T. Kaspar, M. Bowden, S. Spurgeon, B. Matthews, and S. Chambers. 2020. Reversible Oxidation Quantified by Optical Properties in Epitaxial Fe2CrO4+δ Films on (001) MgAl2O4. ACS Omega 5(7), 3240-3249. doi:10.1021/acsomega.9b03299
  • Spurgeon, S., T. Kaspar, V. Shutthanandan, J. Gigax, L. Shao, and M. Sassi. 2020. Asymmetric Lattice Disorder Induced at Oxide Interfaces. Advanced Materials Interfaces 7(8). doi:10.1002/admi.201901944

2019

  • Sassi, M., T. Kaspar, K. Rosso, and S. Spurgeon. 2019. Effect of structure and composition on the electronic excitation induced amorphization of La2Ti2−xZrxO7 ceramics. Scientific Reports 9(1). doi:10.1038/s41598-019-44621-5
  • Scafetta, M., Z. Yang, S. Spurgeon, M. Bowden, T. Kaspar, S. Heald, and S. Chambers. 2019. Epitaxial growth and atomic arrangement in Fe2CrO4 on crystal symmetry matched (001) MgAl2O4. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 37(3). doi:10.1116/1.5093537
  • Kaspar, T., J. Ryan, C. Pantano, J. Rice, C. Trivelpiece, N. Hyatt, C. Corkhill, C. Mann, R. Hand, M. Kirkham, C. Crawford, C. Jantzen, J. Du, X. Lu, M. Harrison, C. Cushman, M. Linford, and N. Smith. 2019. Physical and optical properties of the International Simple Glass. npj Materials Degradation 3(1). doi:10.1038/s41529-019-0069-2
  • Kaspar, T., C. Arendt, D. Neal, S. Riechers, C. Rutherford, A. Schemer-Kohrn, S. Spurgeon, L. Sweet, V. Joshi, C. Lavender, and R. Shimskey. 2019. Characterization of surface layers formed on DU10Mo ingots after processing steps and high humidity exposure. Journal of Nuclear Materials 514, 28-39. doi:10.1016/j.jnucmat.2018.11.022
  • Kaspar, T., P. Sushko, S. Spurgeon, M. Bowden, D. Keavney, R. Comes, S. Saremi, L. Martin, and S. Chambers. 2019. Electronic Structure and Band Alignment of LaMnO3/SrTiO3 Polar/Nonpolar Heterojunctions. Advanced Materials Interfaces 6(1). doi:10.1002/admi.201801428

2018

  • Kaspar, T., S. Hong, M. Bowden, T. Varga, P. Yan, C. Wang, S. Spurgeon, R. Comes, P. Ramuhalli, and C. Henager. 2018. Tuning piezoelectric properties through epitaxy of La2Ti2O7 and related thin films. Scientific Reports 8(1). doi:10.1038/s41598-018-21009-5