PNNL

Dr. Tiffany Kaspar, PhD, joined Pacific Northwest National Laboratory (PNNL) as a graduate student in 2000. After graduation, she continued as a postdoctoral researcher and was hired as a full-time staff scientist in the Physical and Computational Sciences Directorate in 2007.

Dr. Kaspar has nearly 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 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 of Dr. Kaspar’s work.

Previous work focused on the magnetic properties of transition-metal-doped TiO₂ and ZnO as potential dilute magnetic semiconductors. More recent work has investigated 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. Other recent research areas have included the synthesis of lattice-mismatched epitaxial metal films on oxide substrates for both mechanical deformation and 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.

• Epitaxial growth and structural characterization of metallic and metal oxide films
• Magnetic and electronic properties of doped metal oxide films
• Electronic and photochemical characterization of materials relevant for energy applications
• Development of complex oxides as high-temperature piezoelectrics
• Cation and anion transport in oxides under extreme conditions

• PhD in Chemical Engineering, University of Washington (2004)
• BS in Chemical Engineering, University of Colorado, Boulder (1998)

• American Ceramic Society Electronic Materials and Applications (EMA) conference Session S10 organizing committee (2021–present)
• American Vacuum Society (AVS) Magnetic Interfaces and Nanostructures Division Executive Committee (2019–present)
• Environmental Molecular Sciences Laboratory (EMSL) User Executive Committee elected member (2015–2018)
• Pacific Northwest Chapter AVS (PNWAVS): Secretary (2013–present); PNNL Representative (2009–2015); Chair (2012); Vice Chair (2011)
• Co-chair of joint PNWAVS and Surface Analysis 2012 Symposium (June 20–22, 2012)
• AVS (1999–present)
• Argonne National Laboratory's Center for Nanoscale Materials Proposal Review Board

• Fellowship Award, AVS: Science & Technology of Materials, Interfaces, and Processing (2023)
• PNNL Laboratory Director’s Award for Outstanding Contributions to STEM Education: Community Engagement & Outreach (2020)
• Physical Sciences Division Research Highlight: “Creating a Super Lattice: Zipping Electrons, Jumping Holes, and the Quest for Solar Fuels” (2015)
• American Physical Society Outstanding Reviewer (2014)
• Physical Sciences Division Research Highlight: "A rare form of silver observed during routine calibration" (2010)
• Physical Sciences Division Staff Awards and Honors highlight: "Nature Materials highlights careful characterization of candidate spintronic material" (2008)
• EMSL Science Made Possible highlight: "New study shows hidden secondary phases in cobalt-doped zinc oxide" (2008)
• Young Scientist Award, 33rd Physics & Chemistry of Surfaces & Interfaces Conference (2006)

2023

• Adiga P.P., L. Wang, C. Wong, B.E. Matthews, M.E. Bowden, S.R. Spurgeon, and G.E. Sterbinsky, et al. 2023. "Correlation between oxygen evolution reaction activity and surface compositional evolution in epitaxial La0.5Sr0.5Ni1-xFexO3-d thin films." Nanoscale 15, no. 3:1119-1127. PNNL-SA-178044. doi:10.1039/D2NR05373J
• Chrysler M., J. Gabel, T. Lee, Z. Zhu, T.C. Kaspar, M.E. Bowden, and P.V. Sushko, et al. 2023. "Surface termination control of charge transfer and band alignment across a semiconductor-crystalline-oxide heterojunction." Physical Review Materials 7, no. 8:Art. No.084604. PNNL-SA-183613. doi:10.1103/PhysRevMaterials.7.084604
• Kaspar T.C., S.R. Spurgeon, K.H. Yano, B.E. Matthews, M.E. Bowden, C.L. Ophus, and H. Kim, et al. 2023. "Role of structural defects in mediating disordering processes at irradiated epitaxial Fe₃O₄/Cr₂O₃ interfaces." Physical Review Materials 7, no. 9:Art. No. 093604. PNNL-SA-181888. doi:10.1103/PhysRevMaterials.7.093604
• Paudel B., K. Koirala, L. Wang, Z. Zhuo, M.E. Bowden, P.V. Sushko, and W. Yang, et al. 2023. "Epitaxial Growth of Hexagonal BaNiO_3-δ Thin Films on SrTiO₃ (111) Substrates." Physical Review Materials 7. PNNL-SA-184954. doi:10.1103/PhysRevMaterials.7.085004

2022

• Cowles C.C., T.C. Kaspar, R.T. Kouzes, D. Li, Z.W. Bell, I. Ivanov, and E.D. Sword. 2022. "Temperature-Dependent Properties of BC-412 Polyvinyl Toluene Scintillator." IEEE Transactions on Nuclear Science 69, no. 4:942-951. PNNL-SA-166114. doi:10.1109/TNS.2022.3154645
• Kaspar T.C., Y. Du, M.H. Engelhard, D.R. 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: International Journal Devoted to Vacuum, Surfaces, and Films 40, no. 4:Art. No. 41602. PNNL-SA-172072. doi:10.1116/6.0001942
• Kaspar T.C., P. Hatton, K.H. Yano, S.D. Taylor, S.R. Spurgeon, B.P. Uberuaga, and D.K. Schreiber. 2022. "Adatom-driven oxygen intermixing during the deposition of oxide thin films by molecular beam epitaxy." Nano Letters 22, no. 12:4963–4969. PNNL-SA-172523. doi:10.1021/acs.nanolett.2c01678
• Kaspar T.C., D. Li, C.C. Cowles, and R.T. Kouzes. 2022. "Temperature dependence of optical couplant grease transmission at UV and visible wavelengths." IEEE Transactions on Nuclear Science 69, no. 4:952 - 957. PNNL-SA-165830. doi:10.1109/TNS.2022.3154970
• Yano K.H., A. Kohnert, T.C. Kaspar, S.D. Taylor, S.R. Spurgeon, H. Kim, and Y. Wang, et al. 2022. "Dose Rate Dependent Cation & Anion Radiation Enhanced Diffusion in Hematite." Journal of Materials Chemistry A 10, no. 45:24167-24177. PNNL-SA-172572. doi:10.1039/D2TA03403D

2021

• Blanchet M., J. Heath, T.C. Kaspar, B.E. Matthews, S.R. Spurgeon, M.E. Bowden, and S.M. Heald, et al. 2021. "Electronic and Structural Properties of Single-crystal Jahn-Teller Active Co1+xMn2-xO4 Thin Films." Journal of Physics: Condensed Matter 33, no. 12:124002. PNNL-SA-156954. doi:10.1088/1361-648X/abd573
• Efe M., B. Gwalani, J. Tao, M. Song, T.C. Kaspar, A. Devaraj, and A. Rohatgi. 2021. "Nanomechanical Scratching Induced Local Shear Deformation and Microstructural Evolution in Single Crystalline Copper." Applied Surface Science 562. PNNL-SA-158843. doi:10.1016/j.apsusc.2021.150132
• Kaspar T.C., Q. Pang, P.V. Sushko, M.E. Bowden, J. Tao, B. Gwalani, and M.J. Olszta, et al. 2021. "Metastable orientation relationships in thin film Cu-Cr bilayers." Scripta Materialia 194. PNNL-SA-156813. doi:10.1016/j.scriptamat.2020.113635
• Kaspar T.C., S.R. Spurgeon, B.E. Matthews, M.E. Bowden, S.M. Heald, L. Wang, and R. Kelley, et al. 2021. "Incorporation of Ti in epitaxial Fe2TiO4 thin films." Journal of Physics: Condensed Matter 33, no. 31:Article No. 314004. PNNL-SA-160885. doi:10.1088/1361-648X/ac0571
• Kaspar T.C., S.D. Taylor, K.H. Yano, T.G. Lach, Y. Zhou, Z. Zhu, and A. Kohnert, et al. 2021. "Bulk and short-circuit anion diffusion in epitaxial Fe₂O₃ films quantified using buried isotopic tracer layers." Advanced Materials Interfaces 8, no. 9:2001768. PNNL-SA-155914. doi:10.1002/admi.202001768
• Matthews B.E., M. Sassi, C.M. Barr, C. Ophus, T.C. Kaspar, W. Jiang, and K. Hattar, et al. 2021. "Percolation of Ion-Irradiation-Induced Disorder in Complex Oxide Interfaces." Nano Letters 21, no. 12:5353-5359. PNNL-SA-161595. doi:10.1021/acs.nanolett.1c01651
• McRobie C., R. Schoell, T.C. Kaspar, D.K. Schreiber, and D. Kaoumi. 2021. "In Situ Grain Growth of Nanograined Magnetite under Ion Irradiation at Room Temperature and 500℃." Microscopy and Microanalysis 27, no. S1:2640-2643. PNNL-SA-168062. doi:10.1017/S1431927621009351
• Wang L., P.P. Adiga, J. Zhao, W.S. Samarakoon, K.A. Stoerzinger, S.R. Spurgeon, and B.E. Matthews, et al. 2021. "Understanding the Electronic Structure Evolution of Epitaxial LaNi_1-xFe_xO₃ Thin Films for Water Oxidation." Nano Letters 21, no. 19:8324–8331. PNNL-SA-163586. doi:10.1021/acs.nanolett.1c02901
• Yano K.H., A. Kohnert, A. Banerjee, D.J. Edwards, E. Holby, T.C. Kaspar, and H. Kim, et al. 2021. "Radiation-Enhanced Anion Transport in Hematite." Chemistry of Materials 33, no. 7:2307-2318. PNNL-SA-157643. doi:10.1021/acs.chemmater.0c04235
• Yano K.H., A. Kohnert, T.C. Kaspar, S.D. Taylor, S.R. Spurgeon, H. Kim, and Y. Wang, et al. 2021. "Radiation Enhanced Anion Diffusion in Chromia." Journal of Physical Chemistry C 125, no. 50:27820–27827. PNNL-SA-165936. doi:10.1021/acs.jpcc.1c08705

2020

• Lee M., K. Han, J. Lee, Y. Shin, T.C. Kaspar, Y. Chen, and M.H. Engelhard, et al. 2020. "Defect-induced anisotropic surface reactivity and ion transfer processes of anatase nanoparticles." Materials Today Chemistry 17. PNNL-SA-150217. doi:10.1016/j.mtchem.2020.100290
• Scafetta M., T.C. Kaspar, M.E. Bowden, S.R. Spurgeon, B.E. Matthews, and S.A. Chambers. 2020. "Reversible Oxidation Quantified by Optical Properties in Epitaxial Fe2CrO4+d Films on (001) MgAl2O4." ACS Omega 5, no. 7:3240-3249. PNNL-SA-143728. doi:10.1021/acsomega.9b03299
• Yano K.H., S.D. Taylor, T.C. Kaspar, T.G. Lach, and D.K. Schreiber. 2020. "Resolving atomic transport through iron oxide under irradiation using isotopic tracers." Microscopy and Microanalysis 26, no. S2:1108-1110. PNNL-SA-151954. doi:10.1017/S1431927620016979

2019

• Kaspar T.C., C.L. Arendt, D.L. Neal, S.L. Riechers, C.E. Rutherford, A.L. Schemer-Kohrn, and S.R. Spurgeon, et al. 2019. "Characterization of surface layers formed on DU10Mo ingots after processing steps and high humidity exposure." Journal of Nuclear Materials 514. PNNL-SA-136846. doi:10.1016/j.jnucmat.2018.11.022
• Kaspar T.C., J.V. Ryan, C.G. Pantano, J.A. Rice, C. Trivelpiece, N. Hyatt, and C.L. Corkhill, et al. 2019. "Physical and optical properties of the International Simple Glass." npj Materials Degradation 3. PNNL-SA-134932. doi:10.1038/s41529-019-0069-2
• Kaspar T.C., P.V. Sushko, S.R. Spurgeon, M.E. Bowden, D.J. Keavney, R.B. Comes, and S. Saremi, et al. 2019. "Electronic structure and band alignment of LaMnO3 / SrTiO3 polar / non-polar heterojunctions." Advanced Materials Interfaces 6, no. 1:1801428. PNNL-SA-137669. doi:10.1002/admi.201801428
• Sassi M., T.C. Kaspar, K.M. Rosso, and S.R. Spurgeon. 2019. "Effect of structure and composition on the electronic excitation induced amorphization of La2Ti2-xZrxO7 ceramics." Scientific Reports 9, no. 1:Article No. 8190. PNNL-SA-139722. doi:10.1038/s41598-019-44621-5
• Scafetta M., Z. Yang, S.R. Spurgeon, M.E. Bowden, T.C. Kaspar, S.M. Heald, and S.A. Chambers. 2019. "Epitaxial growth and atomic arrangement in Fe2CrO4 on crystal symmetry matched (001) MgAl2O4." Journal of Vacuum Science and Technology A--Vacuum, Surfaces and Films 37, no. 3:Article number 031511. PNNL-SA-141354. doi:10.1116/1.5093537
• Wang L., Y. Du, P.V. Sushko, M.E. Bowden, K.A. Stoerzinger, S.M. Heald, and M. Scafetta, et al. 2019. "Hole-Induced Electronic and Optical Transitions in La1-xSrxFeO3 Epitaxial Thin Films." Physical Review Materials 3, no. 2:Article Number 025401. PNNL-SA-139953. doi:10.1103/PhysRevMaterials.3.025401

2018

• Kaspar T.C., J.T. Reiser, J.V. Ryan, and N.O. Wall. 2018. "Non-destructive characterization of corroded glass surfaces by spectroscopic ellipsometry." Journal of Non-crystalline Solids 481. PNNL-SA-126511. doi:10.1016/j.jnoncrysol.2017.10.054
• Kaspar T.C., S. Hong, M.E. Bowden, T. Varga, P. Yan, C. Wang, and S.R. Spurgeon, et al. 2018. "Tuning piezoelectric properties through epitaxy of La2Ti2O7 and related thin films." Scientific Reports 8. PNNL-SA-128769. doi:10.1038/s41598-018-21009-5

2017

• Chambers S.A., T.C. Droubay, T.C. Kaspar, I.H. Nayyar, M.E. McBriarty, S.M. Heald, and D.J. Keavney, et al. 2017. "Electronic and Optical Properties of a Semiconducting Spinel (Fe2CrO4)." Advanced Functional Materials 27, no. 9:Article No. 1605040. PNNL-SA-121344. doi:10.1002/adfm.201605040
• Kaspar T.C., C.A. Lavender, and M.W. Dibert. 2017. Evaluation of Uranium-235 Measurement Techniques. PNNL-26490. Richland, WA: Pacific Northwest National Laboratory. Evaluation of Uranium-235 Measurement Techniques
• Kaspar T.C., J.G. Gigax, L. Shao, M.E. Bowden, T. Varga, V. Shutthanandan, and S.R. Spurgeon, et al. 2017. "Damage evolution of ion irradiated defected-fluorite La2Zr2O7 epitaxial thin films." Acta Materialia 130. PNNL-SA-121946. doi:10.1016/j.actamat.2017.01.012
• Nayyar I.H., S.E. Chamberlin, T.C. Kaspar, N. Govind, S.A. Chambers, and P.V. Sushko. 2017. "Effect of doping and chemical ordering on the optoelectronic properties of complex oxides: Fe2O3-V2O3 solid solutions and hetero-structures." Physical Chemistry Chemical Physics. PCCP 19, no. 2:1097-1107. PNNL-SA-122741. doi:10.1039/C6CP06087K
• Shutthanandan V., S. Choudhury, S. Manandhar, T.C. Kaspar, C.M. Wang, A. Devaraj, and B.D. Wirth, et al. 2017. "Radiation Tolerant Interfaces: Influence of Local Stoichiometry at the Misfit Dislocation on Radiation Damage Resistance of Metal/Oxide Interfaces." Advanced Materials Interfaces 4, no. 14:Article No. 1700037. PNNL-SA-107725. doi:10.1002/admi.201700037

2016

• Chambers S.A., T.C. Kaspar, A. Prakash, G. Haugstad, and B. Jalan. 2016. "Band alignment at epitaxial BaSnO3/SrTiO3(001) and BaSnO3/LaAlO3(001) heterojunctions." Applied Physics Letters 108, no. 15:Article No. 152104. PNNL-SA-115710. doi:10.1063/1.4946762
• Comes R.B., T.C. Kaspar, S.M. Heald, M.E. Bowden, and S.A. Chambers. 2016. "Infrared Optical Absorption in Low-spin Fe2+-doped SrTiO3." Journal of Physics: Condensed Matter 28, no. 3:Article No. 035901. PNNL-SA-113483. doi:10.1088/0953-8984/28/3/035901
• Kaspar T.C., D.K. Schreiber, S.R. Spurgeon, M.E. McBriarty, G.M. Carroll, D.R. Gamelin, and S.A. Chambers. 2016. "Built-in Potential in Fe2O3-Cr2O3 Superlattices for Improved Photoexcited Carrier Separation." Advanced Materials 28, no. 8:1616-1622. PNNL-SA-112959. doi:10.1002/adma.201504545
• Kaspar T.C., P.V. Sushko, M.E. Bowden, S.M. Heald, A. Papadogianni, C.M. Tschammer, and O. Bierwagen, et al. 2016. "Defect compensation by Cr vacancies and oxygen interstitials in Ti4+-doped Cr2O3 epitaxial thin films." Physical Review. B, Condensed Matter and Materials Physics 94, no. 15:Article No. 155409. PNNL-SA-118171. doi:10.1103/PhysRevB.94.155409
• Schwenzer B., T.C. Kaspar, Y. Shin, and D.W. Gotthold. 2016. "Spectroscopic study of graphene oxide membranes exposed to ultraviolet light." Journal of Physical Chemistry C 120, no. 23:12559-12567. PNNL-SA-116704. doi:10.1021/acs.jpcc.6b03033
• Yu Y., A.Y. Nikiforov, T.C. Kaspar, J.C. Woicik, K.F. Ludwig, S. Gopalan, and U.B. Pal, et al. 2016. "Chemical characterization of surface precipitates in La0.7Sr0.3Co0.2Fe0.8O3-d as cathode material for solid oxide fuel cells." Journal of Power Sources 333. PNNL-SA-117794. doi:10.1016/j.jpowsour.2016.09.166
• Yu Y., K.F. Ludwig, J.C. Woicik, S. Gopalan, U.B. Pal, T.C. Kaspar, and S.N. Basu. 2016. "Effect of Sr Content and Strain on Sr Surface Segregation of La1-xSrxCo0.2Fe0.8O3-delta as Cathode Material for Solid Oxide Fuel Cells." ACS Applied Materials & Interfaces 8, no. 40:26704-26711. PNNL-SA-118616. doi:10.1021/acsami.6b07118

2015

• Comes R.B., S.Y. Smolin, T.C. Kaspar, R. Gao, B.A. Apgar, L.W. Martin, and M.E. Bowden, et al. 2015. "Visible light carrier generation in co-doped epitaxial titanate films." Applied Physics Letters 109, no. 9:Article No. 092901. PNNL-SA-107663. doi:10.1063/1.4913930
• Kaspar T.C., M.E. Bowden, C.M. Wang, V. Shutthanandan, N.R. Overman, R.M. Van Ginhoven, and B.D. Wirth, et al. 2015. "Epitaxial Fe/Y2O3 interfaces as a model system for oxide-dispersion-strengthened ferritic alloys." Journal of Nuclear Materials 457. PNNL-SA-105513. doi:10.1016/j.jnucmat.2014.11.046

2014

• Chamberlin S.E., T.C. Kaspar, M.E. Bowden, V. Shutthanandan, B.C. Kabius, S.M. Heald, and D. Keavney, et al. 2014. "Structural perturbations of epitaxial a-(Fe1-xVx)2O3 thin films driven by excess oxygen near the surface." Journal of Applied Physics 116, no. 23:Article No. 233702. PNNL-SA-105900. doi:10.1063/1.4903839
• Devaraj A., T.C. Kaspar, S. Ramanan, S.K. Walvekar, M.E. Bowden, V. Shutthanandan, and R.J. Kurtz. 2014. "Nanoscale Phase Separation In Epitaxial Cr-Mo and Cr-V Alloy Thin Films Studied Using Atom Probe Tomography: Comparison Of Experiments And Simulation." Journal of Applied Physics 116, no. 19:Article No. 193512. PNNL-SA-105687. doi:10.1063/1.4901465
• Kaspar T.C., M.E. Bowden, C.M. Wang, V. Shutthanandan, S. Manandhar, R.M. Van Ginhoven, and B.D. Wirth, et al. 2014. "Defect Structure of Epitaxial CrxV1 - x Thin Films on MgO(001)." Thin Solid Films 550. PNNL-SA-93687. doi:10.1016/j.tsf.2013.09.067
• Kaspar T.C., S.E. Chamberlin, M.E. Bowden, R.J. Colby, V. Shutthanandan, S. Manandhar, and Y. Wang, et al. 2014. "Impact of Lattice Mismatch and Stoichiometry on the Structure and Bandgap of (Fe,Cr)2O3 Epitaxial Thin Films." Journal of Physics: Condensed Matter 26, no. 13:Article No. 135005. PNNL-SA-99168. doi:10.1088/0953-8984/26/13/135005

2013

• Chamberlin S.E., Y. Wang, K.A. Lopata, T.C. Kaspar, A. Cohn, D.R. Gamelin, and N. Govind, et al. 2013. "Optical Absorption and Spectral Photoconductivity in a-(Fe1-xCrx)2O3 Solid-Solution Thin Films." Journal of Physics: Condensed Matter 25, no. 39:392002. PNNL-SA-95698. doi:10.1088/0953-8984/25/39/392002
• Jaffe J.E., T.C. Kaspar, T.C. Droubay, and T. Varga. 2013. "Band offsets for mismatched interfaces: The special case of ZnO on CdTe (001)." Journal of Vacuum Science and Technology A--Vacuum, Surfaces and Films 31, no. 6:061102. PNNL-SA-90390. doi:10.1116/1.4816951
• Kaspar T.C., S.E. Chamberlin, and S.A. Chambers. 2013. "Surface structure of a-Cr2O3(0001) after activated oxygen exposure." Surface Science 618. PNNL-SA-96080. doi:10.1016/j.susc.2013.09.005
• Kovacs A., A. Ney, A. Ney, M. Duchamp, V. Ney, C. Boothroyd, and P.L. Galindo, et al. 2013. "Defects in paramagnetic Co-doped ZnO films studied by transmission electron microscopy." Journal of Applied Physics 114, no. 24:243503. PNNL-SA-96828. doi:10.1063/1.4851015
• Li B., J. Zhang, T.C. Kaspar, V. Shutthanandan, R.C. Ewing, and J. Lian. 2013. "Multilayered YSZ/GZO films with greatly enhanced ionic conduction for low temperature solid oxide fuel cells." Physical Chemistry Chemical Physics. PCCP 15, no. 4:1296-1301. PNNL-SA-89817. doi:10.1039/C2CP42964K
• Wang C.M., T.C. Kaspar, V. Shutthanandan, A.G. Joly, L. Kovarik, B.W. Arey, and M. Gu, et al. 2013. "Structure And Radiation Damage Behavior Of Epitaxial CrxMo1-x Alloy Thin Films On MgO." Journal of Nuclear Materials 437, no. 1-3:55-61. PNNL-SA-92123. doi:10.1016/j.jnucmat.2013.01.345
• Xia Y., K. Zhu, T.C. Kaspar, Y. Du, B. Birmingham, K.T. Park, and Z. Zhang. 2013. "Atomic Structure of the Anatase TiO2(001) Surface." Journal of Physical Chemistry Letters 4, no. 17:2958-2963. PNNL-SA-96795. doi:10.1021/jz401284u

2012

• Davis J.N., L.J. Miara, L.V. Saraf, T.C. Kaspar, S. Gopalan, U.B. Pal, and J.C. Woicik, et al. 2012. "Hard X-ray Fluorescence Measurements of Heteroepitaxial Solid Oxide Fuel Cell Cathode Materials." ECS Transactions 41, no. 11:19-24. PNNL-SA-84456. doi:10.1149/1.3687387
• Du Y., D. Kim, T.C. Kaspar, S.E. Chamberlin, I. Lyubinetsky, and S.A. Chambers. 2012. "In-situ imaging of the nucleation and growth of epitaxial anatase TiO2(001) films on SrTiO3(001)." Surface Science 606, no. 17-18:1443-1449. PNNL-SA-84680. doi:10.1016/j.susc.2012.05.010
• Kaspar T.C., A. Ney, A. Ney, A.N. Mangham, S.M. Heald, Y. Joly, and V. Ney, et al. 2012. "Structure of epitaxial (Fe,N) codoped rutile TiO2 thin films by x-ray absorption." Physical Review. B, Condensed Matter and Materials Physics 86, no. 3:035322. PNNL-SA-87591. doi:10.1103/PhysRevB.86.035322
• Kaspar T.C., and T.C. Droubay. 2012. "Variation in band offsets at ZnO/Sn:In2O3 (ITO) heterojunctions measured by x-ray photoelectron spectroscopy." Journal of Vacuum Science and Technology A--Vacuum, Surfaces and Films 30, no. 4:04D112. PNNL-SA-85891. doi:10.1116/1.4719541
• Kaspar T.C., M.E. Bowden, T. Varga, C.M. Wang, V. Shutthanandan, A.G. Joly, and B.D. Wirth, et al. 2012. "Structural characterization of epitaxial CrxMo1-x alloy thin films." Journal of Physics: Condensed Matter 24, no. 9:095001. PNNL-SA-81559. doi:10.1088/0953-8984/24/9/095001
• McCloy J.S., C.J. Leslie, T.C. Kaspar, W. Jiang, and R.K. Bordia. 2012. "Magnetic behavior of Ni and Co doped CuMn2O4 spinels." Journal of Applied Physics 111, no. 7:Article No. 07E149. PNNL-SA-82780. doi:10.1063/1.3680530

2011

• Chambers S.A., L. Qiao, T.C. Droubay, T.C. Kaspar, B.W. Arey, and P.V. Sushko. 2011. "Band Alignment, Built-In Potential, and the Absence of Conductivity at the LaCrO3/SrTiO3(001) Heterojunction." Physical Review Letters 107, no. 20:Article No. 206802. PNNL-SA-80654. doi:10.1103/PhysRevLett.107.206802
• Johnson C.A., A. Cohn, T.C. Kaspar, S.A. Chambers, G. Salley, and D.R. Gamelin. 2011. "Visible-light photoconductivity of Zn1-xCoxO and its dependence on Co2+ concentration." Physical Review. B, Condensed Matter 84, no. 12:Article No. 125203. PNNL-SA-79985. doi:10.1103/PhysRevB.84.125203
• Kaspar T.C., T.C. Droubay, and J.E. Jaffe. 2011. "ZnO/Sn:In2O3 and ZnO/CdTe band offsets for extremely thin absorber photovoltaics." Applied Physics Letters 99, no. 26:263504. PNNL-SA-83072. doi:10.1063/1.3672218
• Qiao L., T.C. Droubay, M.E. Bowden, V. Shutthanandan, T.C. Kaspar, and S.A. Chambers. 2011. "LaCrO3 heteroepitaxy on SrTiO3(001) by molecular beam epitaxy." Applied Physics Letters 99, no. 6:Art. No. 061904. PNNL-SA-80732. doi:10.1063/1.3624473
• Qiao L., T.C. Droubay, T. Varga, M.E. Bowden, V. Shutthanandan, Z. Zhu, and T.C. Kaspar, et al. 2011. "Epitaxial growth, structure and intermixing at the LaAlO3/SrTiO3 interface as the film stoichiometry is varied." Physical Review. B, Condensed Matter and Materials Physics 83, no. 8:085408. PNNL-SA-74388. doi:10.1103/PhysRevB.83.085408
• Qiao L., T.C. Droubay, T.C. Kaspar, P.V. Sushko, and S.A. Chambers. 2011. "Cation mixing, band offsets and electric fields at LaAlO3/SrTiO3(001) heterojunctions with variable La:Al atom ratio." Surface Science 605, no. 15-16:1381-1387. PNNL-SA-80121. doi:10.1016/j.susc.2011.04.035
• Wang C.M., T.C. Kaspar, V. Shutthanandan, A.G. Joly, and R.J. Kurtz. 2011. "Structure of Cr Film Epitaxially Grown on MgO (001)." Acta Materialia 59, no. 11:4274-4282. PNNL-SA-75809. doi:10.1016/j.actamat.2011.03.051
• Zhao B., T.C. Kaspar, T.C. Droubay, J.S. McCloy, M.E. Bowden, V. Shutthanandan, and S.M. Heald, et al. 2011. "Electrical transport properties of Ti-doped Fe2O3(0001) epitaxial films." Physical Review. B, Condensed Matter 84, no. 24:245325. PNNL-SA-83375. doi:10.1103/PhysRevB.84.245325

2010

• Droubay T.C., L. Qiao, T.C. Kaspar, M.H. Engelhard, V. Shutthanandan, and S.A. Chambers. 2010. "Non-stoichiometric material transfer in the pulsed laser deposition of LaAlO3." Applied Physics Letters 97, no. 12:124105. PNNL-SA-73524. doi:10.1063/1.3487778
• Jaffe J.E., T.C. Kaspar, T.C. Droubay, T. Varga, M.E. Bowden, and G.J. Exarhos. 2010. "Electronic and defect structure of CuSCN." Journal of Physical Chemistry C 114, no. 19:9111-9117. PNNL-SA-70397. doi:10.1021/jp101586q
• Johnson C.A., K.R. Kittilstved, T.C. Kaspar, T.C. Droubay, S.A. Chambers, G. Salley, and D.R. Gamelin. 2010. "Mid-Gap Electronic States in Zn1 xMnxO." Physical Review. B, Condensed Matter 82, no. 11:Art. No. 115202. PNNL-SA-73651.
• Johnson C.A., T.C. Kaspar, S.A. Chambers, G. Salley, and D.R. Gamelin. 2010. "Sub-band-gap photoconductivity in Co2+-doped ZnO." Physical Review. B, Condensed Matter 81, no. 12:Article Number: 125206. PNNL-SA-72146. doi:10.1103/PhysRevB.81.125206
• Kaspar T.C., T.C. Droubay, and S.A. Chambers. 2010. "Atomic oxygen flux determined by mixed-phase Ag/Ag2O deposition." Thin Solid Films 519, no. 2:635-640. PNNL-SA-71805. doi:10.1016/j.tsf.2010.08.081
• Kaspar T.C., T.C. Droubay, S.A. Chambers, and P.S. Bagus. 2010. "Spectroscopic evidence for Ag(III) in highly oxidized silver films by x-ray photoelectron spectroscopy." Journal of Physical Chemistry C 114, no. 49:21562-21571. PNNL-SA-74545. doi:10.1021/jp107914e
• McCloy J.S., J.V. Ryan, T.C. Droubay, T.C. Kaspar, S.A. Chambers, and D. Look. 2010. "Magnetotransport Properties of High Quality Co:ZnO and Mn:ZnO Single Crystal Pulsed Laser Deposition films: Pitfalls Associated with Magnetotransport on High Resistivity Materials." Review of Scientific Instruments 81, no. 6:Art. No. 063902. PNNL-SA-71740. doi:10.1063/1.3436648
• Miara L.J., L. Piper, J.N. Davis, L.V. Saraf, T.C. Kaspar, S. Basu, and K.E. Smith, et al. 2010. "SURFACE SEGREGATION STUDIES OF SOFC CATHODES: COMBINING SOFT X-RAYS AND ELECTROCHEMICAL IMPEDENCE SPECTROSCOPY." In Materials Research Society (MRS) Symposium Proceedings: Catalytic Materials for Energy, Green Processes and Nanotechnology, November 30 - December 3, 2009, Boston, MA, edited by CY Mou, S Dai, HH Kung and J Liu, 1217, 145-150. Warrendale, Pennsylvania:Materials Research Society. PNNL-SA-70211.
• Ney A., A. Ney, M. Opel, T.C. Kaspar, V. Ney, S. Ye, and K. Ollefs, et al. 2010. "Advanced Spectroscopic Synchrotron Techniques to Unravel the Intrinsic Properties of Dilute Magnetic Oxides: The Case of Co:ZnO." New Journal of Physics 12. PNNL-SA-66420. doi:10.1088/1367-2630/12/1/013020
• Ney A., A. Ney, T. Kammermeier, K. Ollefs, S. Ye, V. Ney, and T.C. Kaspar, et al. 2010. "Anisotropic Paramagnetism of Co-doped ZnO Epitaxial Films." Physical Review. B, Condensed Matter 81, no. 5:Art. No. 054420. PNNL-SA-68802. doi:10.1103/PhysRevB.81.054420
• Ney A., A. Ney, V. Ney, S. Ye, K. Ollefs, T. Kammermeier, and T.C. Kaspar, et al. 2010. "Magnetism of Co doped ZnO with Al codoping: carrier induced mechanisms versus extrinsic origins." Physical Review. B, Condensed Matter and Materials Physics 82, no. 4:041202. PNNL-SA-72647. doi:10.1103/PhysRevB.82.041202
• Ney V., S. Ye, T. Kammermeier, K. Ollefs, A. Ney, A. Ney, and T.C. Kaspar, et al. 2010. "Tuning the magnetic properties of Zn1-xCoxO films." Journal of Magnetism and Magnetic Materials 322, no. 9-12:1232-1234. PNNL-SA-71939. doi:10.1016/j.jmmm.2009.04.024
• Piper L., A. Preston, S. Cho, A. DeMasi, B. Chen, J. Laverock, and K.E. Smith, et al. 2010. "Soft X-Ray Spectroscopic Study of Dense Strontium-Doped Lanthanum Manganite Cathodes for Solid Oxide Fuel Cell Applications." Journal of the Electrochemical Society 158, no. 2:B99-B105. PNNL-SA-72543. doi:10.1149/1.3519075

2009

• Droubay T.C., D. Keavney, T.C. Kaspar, S.M. Heald, C.M. Wang, C.A. Johnson, and K.M. Whitaker, et al. 2009. "Correlated substitution in paramagnetic Mn2+-doped ZnO epitaxial films." Physical Review. B, Condensed Matter and Materials Physics 79, no. 15:Article number:155203. PNNL-SA-62916.
• Droubay T.C., T.C. Kaspar, B.P. Kaspar, and S.A. Chambers. 2009. "Cation dopant distributions in nanostructures of transition-metal doped ZnO:Monte Carlo simulations." Physical Review. B, Condensed Matter and Materials Physics 79, no. 7:Art. No. 075324. PNNL-SA-61451.
• Heald S.M., T.C. Kaspar, T.C. Droubay, and S.A. Chambers. 2009. "Characterization of Thin Films by XAFS: Application to Spintronics Materials." In Materials Science and Technology 2009 Conference and Exhibition, 688-697. Warrendale, Pennsylvania:ASM International. PNNL-SA-66758.
• Heald S.M., T.C. Kaspar, T.C. Droubay, V. Shutthanandan, S.A. Chambers, A. Mokhtari, and A.J. Behan, et al. 2009. "X-ray absorption fine structure and magnetization characterization of the metallic Co component in Co-doped ZnO thin films." Physical Review. B, Condensed Matter 79, no. 7:Art. No. 075202. PNNL-SA-62284.
• Kammermeier T., V. Ney, S. Ye, K. Ollefs, T.C. Kaspar, S.A. Chambers, and F. Wilhelm, et al. 2009. "Element specific measurements of the structural properties and magnetism of CoxZn1-xO." Journal of Magnetism and Magnetic Materials 321, no. 7:699-701. PNNL-SA-65363. doi:10.1016/j.jmmm.2008.11.028

2008

• Kaspar T.C., T.C. Droubay, S.M. Heald, M.H. Engelhard, P. Nachimuthu, and S.A. Chambers. 2008. "Hidden Ferromagnetic Secondary Phases in Cobalt-doped ZnO Epitaxial Thin Films." Physical Review. B, Condensed Matter 77, no. 20:201303. PNNL-SA-58773. doi:10.1103/PhysRevB.77.201303
• Kaspar T.C., T.C. Droubay, S.M. Heald, P. Nachimuthu, C.M. Wang, V. Shutthanandan, and C.A. Johnson, et al. 2008. "Lack of ferromagnetism in n-type cobalt-doped ZnO epitaxial thin films." New Journal of Physics 10. PNNL-SA-58534. doi:10.1088/1367-2630/10/5/055010
• Li Y., T.C. Kaspar, T.C. Droubay, A.G. Joly, P. Nachimuthu, Z. Zhu, and V. Shutthanandan, et al. 2008. "A Study of H and D doped ZnO epitaxial films grown by pulsed laser deposition." Journal of Applied Physics 104, no. 5:Article no. 053711. PNNL-SA-62192. doi:10.1063/1.2975219
• Li Y., T.C. Kaspar, T.C. Droubay, Z. Zhu, V. Shutthanandan, P. Nachimuthu, and S.A. Chambers. 2008. "Electronic properties of H and D doped ZnO epitaxial films." Applied Physics Letters 92, no. 15:Art. No. 152105. PNNL-SA-59567.
• Ney A., A. Ney, K. Ollefs, S. Ye, T. Kammermeier, V. Ney, and T.C. Kaspar, et al. 2008. "Absence of Intrinsic Ferromagnetic Interactions of Isolated and Paired Co Dopant Atoms in Zn1-xCoxO with High Structural Perfection." Physical Review Letters 100, no. 15:Art. No. 157201. PNNL-SA-57805. doi:10.1103/PhysRevLett.100.157201

2006

• Kaspar T.C., T.C. Droubay, D.E. McCready, P. Nachimuthu, S.M. Heald, C.M. Wang, and A.S. Lea, et al. 2006. "Magnetic properties of epitaxial Co-doped anatase TiO2 thin films with excellent structural quality." Journal of Vacuum Science and Technology B--Microelectronics and Nanometer Structures 24, no. 4:2012-2017. PNNL-SA-48059. doi:10.1116/1.2216723
• Kaspar T.C., T.C. Droubay, V. Shutthanandan, S.M. Heald, C.M. Wang, D.E. McCready, and S. Thevuthasan, et al. 2006. "Ferromagnetism and structure of epitaxial Cr-doped anatase TiO2 thin films." Physical Review. B, Condensed Matter and Materials Physics 73, no. 15:155327 (12 p.). PNNL-SA-47923. doi:10.1103/PhysRevB.73.155327
• Shutthanandan V., S. Thevuthasan, T.C. Droubay, T.C. Kaspar, A. Punnoose, J. Hays, and S.A. Chambers. 2006. "Quantification of Dopant Concentrations in Diluted Magnetic Semiconductors using Ion Beam Techniques." Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms 249, no. 1-2:402-405. PNNL-SA-46992. doi:10.1016/j.nimb.2006.04.038

2005

• Chambers S.A., T.C. Droubay, and T.C. Kaspar. 2005. "Epitaxial Growth and Properties of Magnetically Doped TiO2." In Thin Films and Heterostructures for Oxide Electronics, edited by Satishchandra B. Ogale. 219-247. New York, New York:Springer. PNNL-SA-42461.
• Kaspar T.C., S.M. Heald, C.M. Wang, J.D. Bryan, T.C. Droubay, V. Shutthanandan, and S. Thevuthasan, et al. 2005. "Negligible Magnetism in Excellent Structural Quality CrxTi1-xO2 Anatase: Contrast with High-Tc Ferromagnetism in Structurally Defective CrxTi1-xO2." Physical Review Letters 95. PNNL-SA-45771. doi:10.1103/PhysRevLett.95.217203
• Kaspar T.C., T.C. Droubay, C.M. Wang, S.M. Heald, A.S. Lea, and S.A. Chambers. 2005. "Co-doped Anatase TiO2 Heteroepitaxy on Si(001)." Journal of Applied Physics 97, no. 7:073511-073511-10. PNNL-SA-42653. doi:10.1063/1.1868854
• Osterwalder J., T.C. Droubay, T.C. Kaspar, J.R. Williams, C.M. Wang, and S.A. Chambers. 2005. "Growth of Cr-doped TiO2 Films in the Rutile and Anatase Structures by Oxygen Plasma Assisted Molecular Beam Epitaxy." Thin Solid Films 484, no. 1-2:289-298. PNNL-SA-42647.

2004

• Chambers S.A., T.C. Droubay, T.C. Kaspar, and M.S. Gutowski. 2004. "Accurate Valence Band Maximum Determination for SrTiO3(001)." Surface Science 554, no. 2-3:81-89. PNNL-SA-39651.
• Chambers S.A., T.C. Droubay, T.C. Kaspar, and M.S. Gutowski. 2004. "Experimental Determination of Valence Band Maxima for SrTiO3, TiO2, and SrO and the Associated Valence Band Offsets with Si(001)." Journal of Vacuum Science and Technology B--Microelectronics and Nanometer Structures 22, no. 4:2205-2215. PNNL-SA-39659.
• Chambers S.A., T.C. Droubay, T.C. Kaspar, and M.S. Gutowski. 2004. "Experimental determination of valence band maxima for SrTiO3,TiO2, and SrO and the associated valence band offsets with Si(001)." In 31st Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI). Published in Journal of Vacuum Science and Technology B, 22, 2205-2215. New York, New York:American Vacuum Society. PNNL-SA-43069. doi: http://dx.doi.org/10.1116/1.1768525
• Shutthanandan V., S. Thevuthasan, S.M. Heald, T.C. Droubay, M.H. Engelhard, T.C. Kaspar, and D.E. McCready, et al. 2004. "Room Temperature Ferromagnetism in Ion-implanted Co-doped TiO2(110) Rutile." Applied Physics Letters 84, no. 22:4466-4468. PNNL-SA-40229.
• Shutthanandan V., S. Thevuthasan, S.M. Heald, T.C. Droubay, M.H. Engelhard, T.C. Kaspar, and D.E. McCready, et al. 2004. "Room-Temperature Ferromagnetism in Ion-Implanted Co-Doped TiO2(110) Rutile." Applied Physics Letters 84, no. 22:4466-4468. PNNL-SA-43204.

2003

• Kaspar T.C., A.C. Tuan, R.G. Tonkyn, W.P. Hess, J. Rogers, Jr., and Y. Ono. 2003. "The Role of O(1D) in the Oxidation of Si(100)." Journal of Vacuum Science and Technology B--Microelectronics and Nanometer Structures 21, no. 2:895-899. PNWD-SA-5762.
• Tuan A.C., T.C. Kaspar, T.C. Droubay, J.W. Rogers, and S.A. Chambers. 2003. "Band Offsets for the Epitaxial TiO2/SrTiO3/Si(001) System." Applied Physics Letters 83, no. 18:3734-3736. PNNL-SA-39168.