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Tiffany Kaspar

Tiffany Kaspar

Materials Sciences
Scientist
Pacific Northwest National Laboratory
PO Box 999
MSIN: K8-87
Richland, WA 99352
509/371-6503

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 Scott Chambers' Oxide Epitaxy group in 2007.

Dr. Kaspar's research interests include the epitaxial growth (via oxygen-plasma-assisted molecular beam epitaxy or pulsed laser deposition) and structural characterization of metallic and metal oxide films. Structure-property relationships can then be made with physical phenomena such as magnetic and electronic properties. 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. Other recent research areas have included the structural characterization of lattice-mismatched epitaxial metal films on oxide substrates for radiation damage studies, electronic characterization of ZnO-based materials relevant for solar photovoltaics, and pulsed laser deposition of complex oxides for solid oxide fuel cell applications.

Research Interests

  • Epitaxial growth and structural characterization of metallic and metal oxide films
  • Magnetic and electronic properties of doped metal oxide films
  • Electronic characterization of materials relevant for solar photovoltaics
  • Pulsed laser deposition of complex oxides for solid oxide fuel cell applications

Education and Credentials

  • University of Colorado, Boulder, CO, B.S.Chemical Engineering, (1998)
  • University of Washington, Seattle, WA, Ph.D., Chemical Engineering, (2004)
  • Pacific Northwest National Lab, Richland, WA, Post-doctoral Fellow, (2004-07)

Affiliations and Professional Service

  • American Vacuum Society (1999-present)
  • Pacific Northwest Chapter AVS (PNWAVS) Vice-Chair (2011)
  • PNWAVS Chair (2012)
  • Co-chair of joint PNWAVS and Surface Analysis 2012 National Symposium, June 20-22, 2012 in EMSL, Richland, WA
  • Serve on Argonne National Laboratory’s Center for Nanoscale Materials (CNM) Proposal Review Board

Awards and Recognitions

  • 2010: Fundamental and Computation Sciences Directorate Chemical and Materials Sciences Division Research Highlights: “A rare form of silver observed during routine calibration,” http://www.pnl.gov/science/highlights/highlight.asp?groupid=756&id=876
  • 2008: Fundamental and Computational Sciences Directorate Staff Awards and Honors highlight: “Nature Materials highlights careful characterization of candidate spintronic material,” http://www.pnl.gov/science/highlights/highlight.asp?id=456
  • 2008: EMSL Science Made Possible highlight: “New study shows hidden secondary phases in cobalt-doped zinc oxide,” http://www.emsl.pnl.gov/news/inbriefs/docs/spintronic_20080625.pdf
  • 2004 " 2006: Joint Institute for Nanoscience Postdoctoral Fellowship
  • 2006: Young Scientist Award, 33rd PCSI Conference

PNNL Publications

2014

  • Kaspar TC, SE Chamberlin, ME Bowden, RJ Colby, V Shutthanandan, S Manandhar, Y Wang, P Sushko, and SA Chambers. 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(13):Article No. 135005.  doi:10.1088/0953-8984/26/13/135005

2013

  • Chamberlin SE, Y Wang, KA Lopata, TC Kaspar, A Cohn, DR Gamelin, N Govind, PV Sushko, and SA Chambers. 2013. "Optical Absorption and Spectral Photoconductivity in a-(Fe1-xCrx)2O3 Solid-Solution Thin Films." Journal of Physics: Condensed Matter 25(39):392002.  doi:10.1088/0953-8984/25/39/392002
  • Jaffe JE, TC Kaspar, T 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(6):061102.  doi:10.1116/1.4816951
  • Li B, J Zhang, TC Kaspar, V Shutthanandan, RC 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(4):1296-1301.  doi:10.1039/C2CP42964K
  • Wang CM, TC Kaspar, V Shutthanandan, AG Joly, L Kovarik, BW Arey, M Gu, A Devaraj, BD Wirth, and RJ Kurtz. 2013. "Structure And Radiation Damage Behavior Of Epitaxial CrxMo1-x Alloy Thin Films On MgO." Journal of Nuclear Materials 437(1-3):55-61.  doi:10.1016/j.jnucmat.2013.01.345

2012

  • Kaspar TC, A Ney, AN Mangham, SM Heald, Y Joly, V Ney, F Wilhelm, A Rogalev, F Yakou, and SA Chambers. 2012. "Structure of epitaxial (Fe,N) codoped rutile TiO2 thin films by x-ray absorption." Physical Review. B, Condensed Matter and Materials Physics 86(3):035322.  doi:10.1103/PhysRevB.86.035322
  • Kaspar TC, and T 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(4): 04D112.  doi:10.1116/1.4719541
  • Kaspar TC, ME Bowden, T Varga, CM Wang, V Shutthanandan, AG Joly, BD Wirth, and RJ Kurtz. 2012. "Structural characterization of epitaxial CrxMo1-x alloy thin films." Journal of Physics. Condensed Matter 24(9):095001.  doi:10.1088/0953-8984/24/9/095001
  • Davis JN, LJ Miara, LV Saraf, TC Kaspar, S Gopalan, UB Pal, JC Woicik, SN Basu, and KF Ludwig. 2012. "Hard X-ray Fluorescence Measurements of Heteroepitaxial Solid Oxide Fuel Cell Cathode Materials." ECS Transactions 41(11):19-24.  doi:10.1149/1.3687387
  • Du Y, DJ Kim, TC Kaspar, SE Chamberlin, I Lyubinetsky, and SA Chambers. 2012. "In-situ imaging of the nucleation and growth of epitaxial anatase TiO2(001) films on SrTiO3(001)." Surface Science 606(17-18):1443-1449.  doi:10.1016/j.susc.2012.05.010
  • McCloy JS, CJ Leslie, TC Kaspar, W Jiang, and RK Bordia. 2012. "Magnetic behavior of Ni and Co doped CuMn2O4 spinels." Journal of Applied Physics 111(7):Article No. 07E149. 

2011

  • Kaspar TC, T Droubay, and JE Jaffe. 2011. "ZnO/Sn:In2O3 and ZnO/CdTe band offsets for extremely thin absorber photovoltaics ." Applied Physics Letters 99(26):263504.  doi:10.1063/1.3672218
  • Qiao L, T Droubay, ME Bowden, V Shutthanandan, TC Kaspar, and SA Chambers. 2011. "LaCrO3 heteroepitaxy on SrTiO3(001) by molecular beam epitaxy ." Applied Physics Letters 99(6):Art. No. 061904.  doi:10.1063/1.3624473
  • Qiao L, T Droubay, T Varga, ME Bowden, V Shutthanandan, Z Zhu, TC Kaspar, and SA Chambers. 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(8):085408.  doi:10.1103/PhysRevB.83.085408
  • Qiao L, T Droubay, TC Kaspar, PV Sushko, and SA Chambers. 2011. "Cation mixing, band offsets and electric fields at LaAlO3/SrTiO3(001) heterojunctions with variable La:Al atom ratio." Surface Science 605(15-16):1381-1387.  doi:10.1016/j.susc.2011.04.035
  • Chambers SA, L Qiao, T Droubay, TC Kaspar, BW Arey, and PV Sushko. 2011. "Band Alignment, Built-In Potential, and the Absence of Conductivity at the LaCrO3/SrTiO3(001) Heterojunction." Physical Review Letters 107(20):Article No. 206802.  doi:10.1103/PhysRevLett.107.206802
  • Johnson CA, A Cohn, TC Kaspar, SA Chambers, GM Salley, and DR Gamelin. 2011. "Visible-light photoconductivity of Zn1-xCoxO and its dependence on Co2+ concentration." Physical Review. B, Condensed Matter 84(12):Article No. 125203.  doi:10.1103/PhysRevB.84.125203
  • Wang CM, TC Kaspar, V Shutthanandan, AG Joly, and RJ Kurtz. 2011. "Structure of Cr Film Epitaxially Grown on MgO (001)." Acta Materialia 59(11):4274-4282.  doi:10.1016/j.actamat.2011.03.051
  • Zhao B, TC Kaspar, T Droubay, JS McCloy, ME Bowden, V Shutthanandan, SM Heald, and SA Chambers. 2011. "Electrical transport properties of Ti-doped Fe2O3(0001) epitaxial films." Physical Review. B, Condensed Matter 84(24):245325.  doi:10.1103/PhysRevB.84.245325

2010

  • Kaspar TC, T Droubay, and SA Chambers. 2010. "Atomic oxygen flux determined by mixed-phase Ag/Ag2O deposition." Thin Solid Films 519(2):635-640.  doi:10.1016/j.tsf.2010.08.081
  • Kaspar TC, T Droubay, SA Chambers, and PS Bagus. 2010. "Spectroscopic evidence for Ag(III) in highly oxidized silver films by x-ray photoelectron spectroscopy." Journal of Physical Chemistry C 114(49):21562-21571.  doi:10.1021/jp107914e
  • Droubay T, L Qiao, TC Kaspar, MH Engelhard, V Shutthanandan, and SA Chambers. 2010. "Non-stoichiometric material transfer in the pulsed laser deposition of LaAlO3." Applied Physics Letters 97(12):124105.  doi:10.1063/1.3487778
  • Jaffe JE, TC Kaspar, T Droubay, T Varga, ME Bowden, and GJ Exarhos. 2010. "Electronic and defect structure of CuSCN." Journal of Physical Chemistry C 114(19):9111-9117.  doi:10.1021/jp101586q
  • Johnson CA, TC Kaspar, SA Chambers, GM Salley, and DR Gamelin. 2010. "Sub-band-gap photoconductivity in Co2+-doped ZnO." Physical Review. B, Condensed Matter 81(12):Article Number: 125206 .  doi:10.1103/PhysRevB.81.125206
  • Johnson CA, KR Kittilstved, TC Kaspar, T Droubay, SA Chambers, GM Salley, and DR Gamelin. 2010. "Mid-Gap Electronic States in Zn1 xMnxO." Physical Review. B, Condensed Matter 82(11):Art. No. 115202. 
  • McCloy JS, JV Ryan, T Droubay, TC Kaspar, SA 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(6):Art. No. 063902.  doi:10.1063/1.3436648
  • Miara LJ, LFJ Piper, JN Davis, LV Saraf, TC Kaspar, S Basu, KE Smith, UB Pal, and S Gopalan. 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, vol. 1217, ed. CY Mou, S Dai, HH Kung and J Liu, pp. 145-150.  Materials Research Society, Warrendale, PA. 
  • Ney A, M Opel, TC Kaspar, V Ney, S Ye, K Ollefs, T Kammermeier, S Bauer, KW Nielsen, ST Goennenwein, MH Engelhard, S Zhou, K Potzger, J Simon, W Mader, SM Heald, JC Cezar, F Wilhelm, A Rogalev, R Gross, and SA Chambers. 2010. "Advanced Spectroscopic Synchrotron Techniques to Unravel the Intrinsic Properties of Dilute Magnetic Oxides: The Case of Co:ZnO." New Journal of Physics 12:Art. No. 013020.  doi:10.1088/1367-2630/12/1/013020
  • Ney A, T Kammermeier, K Ollefs, S Ye, V Ney, TC Kaspar, SA Chambers, F Wilhelm, and A Rogalev. 2010. "Anisotropic Paramagnetism of Co-doped ZnO Epitaxial Films." Physical Review. B, Condensed Matter 81(5):Art. No. 054420.  doi:10.1103/PhysRevB.81.054420
  • Ney A, V Ney, S Ye, K Ollefs, T Kammermeier, TC Kaspar, SA Chambers, F Wilhelm, and A Rogalev. 2010. "Magnetism of Co doped ZnO with Al codoping: carrier induced mechanisms versus extrinsic origins ." Physical Review. B, Condensed Matter and Materials Physics 82(4):041202.  doi:10.1103/PhysRevB.82.041202
  • Ney V, S Ye, T Kammermeier, K Ollefs, A Ney, TC Kaspar, SA Chambers, F Wilhelm, and A Rogalev. 2010. "Tuning the magnetic properties of Zn1-xCoxO films." Journal of Magnetism and Magnetic Materials 322(9-12):1232-1234.  doi:10.1016/j.jmmm.2009.04.024
  • Piper LFJ, ARH Preston, SW Cho, A DeMasi, B Chen, J Laverock, KE Smith, LJ Miara, JN Davis, S Basu, UB Pal, S Gopalan, LV Saraf, TC Kaspar, AY Matsuura, PA Glans, and J Guo. 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(2):B99-B105.  doi:10.1149/1.3519075

2009

  • Droubay T, TC Kaspar, BP Kaspar, and SA Chambers. 2009. "Cation dopant distributions in nanostructures of transition-metal doped ZnO:Monte Carlo simulations." Physical Review. B, Condensed Matter and Materials Physics 79(7):Art. No. 075324. 
  • Droubay T, D Keavney, TC Kaspar, SM Heald, CM Wang, CA Johnson, KM Whitaker, DR Gamelin, and SA Chambers. 2009. "Correlated substitution in paramagnetic Mn2+-doped ZnO epitaxial films." Physical Review. B, Condensed Matter and Materials Physics 79(15):Article number:155203. 
  • Heald SM, TC Kaspar, T Droubay, and SA Chambers. 2009. "Characterization of Thin Films by XAFS: Application to Spintronics Materials." In Materials Science and Technology 2009 Conference and Exhibition, pp. 688-697.  ASM International, Warrendale, PA. 
  • Heald SM, TC Kaspar, T Droubay, V Shutthanandan, SA Chambers, A Mokhtari, AJ Behan, HJ Blythe, JR Neal, M Fox, and G Gehring. 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(7):Art. No. 075202. 
  • Kammermeier T, V Ney, S Ye, K Ollefs, TC Kaspar, SA Chambers, F Wilhelm, A Rogalev, and A Ney. 2009. "Element specific measurements of the structural properties and magnetism of CoxZn1-xO." Journal of Magnetism and Magnetic Materials 321 (7):699-701 .  doi:10.1016/j.jmmm.2008.11.028

2008

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

2006

  • Kaspar TC, T Droubay, DE McCready, P Nachimuthu, SM Heald, CM Wang, AS Lea, V Shutthanandan, SA Chambers, and MF Toney. 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(4):2012-2017.  doi:10.1116/1.2216723
  • Kaspar TC, T Droubay, V Shutthanandan, SM Heald, CM Wang, DE McCready, S Thevuthasan, JD Bryan, DR Gamelin, AJ Kellock, MF Toney, X Hong, C Ahn, and SA Chambers. 2006. "Ferromagnetism and structure of epitaxial Cr-doped anatase TiO2 thin films." Physical Review. B, Condensed Matter and Materials Physics 73(15):155327 (12 p.).  doi:10.1103/PhysRevB.73.155327
  • Shutthanandan V, S Thevuthasan, T Droubay, TC Kaspar, A Punnoose, J Hays, and SA 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(1-2):402-405.  doi:10.1016/j.nimb.2006.04.038

2005

  • Kaspar TC, T Droubay, CM Wang, SM Heald, AS Lea, and SA Chambers. 2005. "Co-doped Anatase TiO2 Heteroepitaxy on Si(001)." Journal of Applied Physics 97(7):073511-073511-10.  doi:10.1063/1.1868854
  • Kaspar TC, SM Heald, CM Wang, JD Bryan, T Droubay, V Shutthanandan, S Thevuthasan, DE McCready, AJ Kellock, DR Gamelin, and SA Chambers. 2005. "Negligible Magnetism in Excellent Structural Quality CrxTi1-xO2 Anatase: Contrast with High-Tc Ferromagnetism in Structurally Defective CrxTi1-xO2." Physical Review Letters 95:217203.  doi:10.1103/PhysRevLett.95.217203
  • Chambers SA, T Droubay, and TC Kaspar. 2005. "Epitaxial Growth and Properties of Magnetically Doped TiO2." Chapter 7 in Thin Films and Heterostructures for Oxide Electronics, ed. Satishchandra B. Ogale, pp. 219-247.  Springer, New York, NY. 
  • Osterwalder J, T Droubay, TC Kaspar, JR Williams, CM Wang, and SA 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(1-2):289-298. 

2004

  • Chambers SA, T Droubay, TC Kaspar, and MS Gutowski. 2004. "Accurate Valence Band Maximum Determination for SrTiO3(001) ." Surface Science 554(2-3):81-89. 
  • Chambers SA, T Droubay, TC Kaspar, and MS 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(4):2205-2215. 
  • Chambers SA, TC Droubay, TC Kaspar, and MS 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, vol. 22, no. 4, pp. 2205-2215.  American Vacuum Society, New York, NY.  doi:http://dx.doi.org/10.1116/1.1768525
  • Shutthanandan V, S Thevuthasan, SM Heald, T Droubay, MH Engelhard, TC Kaspar, DE McCready, LV Saraf, SA Chambers, BS Mun, NM Hamdan, P Nachimuthu, B Taylor, R Sears, and B Sinkovic. 2004. "Room Temperature Ferromagnetism in Ion-implanted Co-doped TiO2(110) Rutile." Applied Physics Letters 84(22):4466-4468. 
  • Shutthanandan V, S Thevuthasan, SM Heald, T Droubay, MH Engelhard, TC Kaspar, DE McCready, LV Saraf, SA Chambers, BS Mun, NM Hamdan, P Nachimuthu, B Taylor, R Sears, and B Sinkovic. 2004. "Room-Temperature Ferromagnetism in Ion-Implanted Co-Doped TiO2(110) Rutile." Applied Physics Letters 84(22):4466-4468. 

2003

  • Kaspar TC, AC Tuan, RG Tonkyn, WP Hess, JW 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(2):895-899. 
  • Tuan AC, TC Kaspar, T Droubay, JW Rogers, Jr, and SA Chambers. 2003. "Band Offsets for the Epitaxial TiO2/SrTiO3/Si(001) System." Applied Physics Letters 83(18):3734-3736. 

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