PNNL

Dr. Timothy C. Droubay is a senior staff scientist in the Oxide Epitaxy group in the Physical and Computational Sciences Directorate at Pacific Northwest National (PNNL). After becoming a staff scientist in 2002, Dr. Droubay has conducted materials research in the growth of complex metal oxide films, nanoparticles, and multilayers deposited by pulsed laser deposition and reactive oxygen assisted molecular beam epitaxy. The current thrust of his research focusses on the interplay of structural, electronic, and magnetic properties of transition metal oxides, complex oxides, nanoparticles, and multilayers. Dr. Droubay has been instrumental in the development and maintenance of the laboratory's two molecular beam epitaxy systems and pulsed laser deposition systems, along with PNNL’s laboratory-based x-ray absorption and x-ray emission spectroscopy capabilities. He also leads the Oxide Epitaxy Laboratory's electrotransport, magnetotransport, and magnetic measurements capabilities in the Energy Sciences Center. 

Prior to joining PNNL in 2000, Dr. Droubay served as a physics instructor at the Waukesha County Technical College and University of Wisconsin, Milwaukee where he taught undergraduate physics courses designed primarily engineering, medical technology, and pre-med students.

• Novel electronic and magnetic properties of oxide thin films and their interfaces, multilayers, and superlattices.
• Epitaxial growth and stabilization of all-epitaxial Josephson Junction qubits.
• Synthesis of metastable binary and complex oxides, nitrides, oxi-hydroxides, and multilayers for technological applications.
• Next generation light-source photocathode materials.

• PhD in Physics, University of Wisconsin, Milwaukee
• MS in Physics, University of Wisconsin, Milwaukee
• BS in Mathematics and Physics, University of Puget Sound, Tacoma

• American Physical Society
• American Vacuum Society
• Materials Research Society

• Rising Star Award, PNNL (2019)
• Science and Engineering Development Program Award Recipient, PNNL (2006)
• Distinguished Lecturer, PNNL Nanoscience Short Course (2003)

2021

• Jin T., E.L. Rivers, D. Kim, T.C. Droubay, E.P. Jahrman, D. Mar, and B.L. Weese, et al. 2021. "Effect of Chlorine and Chromium on Sulfur Solubility in Low-Activity Waste Glass." International Journal of Applied Glass Science. PNNL-SA-146955. doi:10.1111/ijag.16540
• Kirby B.W., J.S. Hardy, C.A. Coyle, N.L. Canfield, and T.C. Droubay. 2021. "Sr and Co Vapor-Phase Transport from LSCF Cathodes." In 17th International Symposium on Solid Oxide Fuel Cells (SOFC-XVII) July 18, 2021 - July 23, 2021 Stockholm, USA. ECS Transactions, 103, 1415-1424. Bristol:IOP Publishing. PNNL-SA-163853. doi:10.1149/101301.1415ecst

2019

• Devanathan R., W. Jiang, K. Kruska, M.A. Conroy, T.C. Droubay, and J.M. Schwantes. 2019. "Hexagonal Close-Packed High-Entropy Alloy Formation under Extreme Processing Conditions." Journal of Materials Research 34, no. 5:709-719. PNNL-SA-137859. doi:10.1557/jmr.2018.438
• Jiang W., M.A. Conroy, K. Kruska, M.J. Olszta, T.C. Droubay, J.M. Schwantes, and C.A. Taylor, et al. 2019. "In situ Study of Particle Precipitation in Metal-doped CeO2 during Thermal Treatment and Ion Irradiation for Emulation of Irradiating Fuels." Journal of Physical Chemistry C 123, no. 4:2591-2601. PNNL-SA-139442. doi:10.1021/acs.jpcc.8b11027
• Stoerzinger K.A., C.I. Pearce, T.C. Droubay, V. Shutthanandan, Z. Liu, E. Arenholz, and K.M. Rosso. 2019. "Structure, Magnetism, and the Interaction of Water with Ti-Doped Fe3O4 Surfaces." Langmuir 35, no. 43:13872-13879. PNNL-SA-145960. doi:10.1021/acs.langmuir.9b02468

2018

• Elsaidi S.K., M.A. Sinnwell, A. Devaraj, T.C. Droubay, Z. Nie, V. Murugesan, and B.P. McGrail, et al. 2018. "Extraction of Rare Earth Elements using Magnetite@MOF Composites." Journal of Materials Chemistry A 6, no. 38:18438-18443. PNNL-SA-136516. doi:10.1039/c8ta04750b
• Spurgeon S.R., P.V. Sushko, A. Devaraj, Y. Du, T.C. Droubay, and S.A. Chambers. 2018. "Onset of Phase Separation in the Double Perovskite Oxide La2MnNiO6." Physical Review B 97, no. 13:134110. PNNL-SA-123784. doi:10.1103/PhysRevB.97.134110
• Varga T., T.C. Droubay, L. Kovarik, D. Hu, and S.A. Chambers. 2018. "Controlling the structure and ferroic properties of strained epitaxial NiTiO3 thin films on sapphire by post-deposition annealing." Thin Solid Films 662. PNNL-SA-129160. doi:10.1016/j.tsf.2018.07.030
• Woicik J.C., J. Ablett, N. Quackenbush, A. Rumaiz, C.R. Weiland, T.C. Droubay, and S.A. Chambers. 2018. "Experimental assignment of many-electron excitations in the photoionization of NiO." Physical Review. B, Condensed Matter and Materials Physics 97, no. 24:245142. PNNL-SA-131960. doi:10.1103/PhysRevB.97.245142
• Yang Z., P. Ong, Y. He, L. Wang, M.E. Bowden, W. Xu, and T.C. Droubay, et al. 2018. "Direct Visualization of Li Dendrite Effect on LiCoO2 Cathode by In Situ TEM." Small 14, no. 52:1803108. PNNL-SA-135382. doi:10.1002/smll.201803108

2017

• Chambers S.A., M.H. Engelhard, L. Wang, T.C. Droubay, M.E. Bowden, M.J. Wahila, and N. Quackenbush, et al. 2017. "X-ray photoelectron spectra for single-crystal Ti2O3: experiment and theory." Physical Review. B, Condensed Matter and Materials Physics 96, no. 20:205143. PNNL-SA-127619. doi:10.1103/PhysRevB.96.205143
• 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
• Engelhard M.H., T.C. Droubay, and Y. Du. 2017. "X-Ray photoelectron Spectroscopy Applications." In Encyclopedia of Spectroscopy and Spectrometry, 3rd edition. 716-724. Oxford:Academic Press. PNNL-SA-111274. doi:10.1016/B978-0-12-409547-2.12102-X
• Jiang W., M.A. Conroy, K. Kruska, N.R. Overman, T.C. Droubay, J. Gigax, and L. Shao, et al. 2017. "Nanoparticle Precipitation in Irradiated and Annealed Ceria Doped with Metals for Emulation of Spent Fuels." Journal of Physical Chemistry C 121, no. 40:22465-22477. PNNL-SA-126918. doi:10.1021/acs.jpcc.7b06188
• Ngai J., K. Ahmadi-Majlan, M.J. Moghadam, M. Chrysler, D. Kumah, F. Walker, and C. Ahn, et al. 2017. "Electrically coupling complex oxides to semiconductors: a route to novel material functionalities." Journal of Materials Research 32, no. 2:249-259. PNNL-SA-119030. doi:10.1557/jmr.2016.496
• Stoerzinger K.A., C.I. Pearce, T.C. Droubay, V. Shutthanandan, A. Shavorskiy, H. Bluhm, and K.M. Rosso. 2017. "Impact of Ti Incorporation on Hydroxylation and Wetting of Fe3O4." Journal of Physical Chemistry C 121, no. 35:19288-19295. PNNL-SA-128589. doi:10.1021/acs.jpcc.7b06258
• Varga T., T.C. Droubay, L. Kovarik, M.I. Nandasiri, V. Shutthanandan, D. Hu, and B. Kim, et al. 2017. "Coupled Lattice Polarization and Ferromagnetism in Multiferroic NiTiO3 Thin Films." ACS Applied Materials & Interfaces 9, no. 26:21879-21890. PNNL-SA-121771. doi:10.1021/acsami.7b04481

2016

• Spurgeon S.R., Y. Du, T.C. Droubay, A. Devaraj, X. Sang, P. Longo, and P. Yan, et al. 2016. "Competing Pathways for Nucleation of the Double Perovskite Structure in the Epitaxial Synthesis of La2MnNiO6." Chemistry of Materials 28, no. 11:3814-3822. PNNL-SA-115671. doi:10.1021/acs.chemmater.6b00829
• Xu P., T.C. Droubay, J.S. Jeong, K.A. Mkhoyan, P.V. Sushko, S.A. Chambers, and B. Jalan. 2016. "Quasi 2D Ultrahigh Carrier Density in a Complex Oxide Broken Gap Heterojunction." Advanced Materials Interfaces 3, no. 2:Article No. 1500432. PNNL-SA-107557. doi:10.1002/admi.201500432

2015

• Cao Y., K. Xu, W. Jiang, T.C. Droubay, P. Ramuhalli, D.J. Edwards, and B.R. Johnson, et al. 2015. "Hysteresis in single and polycrystalline iron thin films: major and minor loops, first order reversal curves, and Preisach modeling." Journal of Magnetism and Magnetic Materials 395. PNNL-SA-110829. doi:10.1016/j.jmmm.2015.06.072
• Chambers S.A., Y. Du, M. Gu, T.C. Droubay, S. Hepplestone, and P.V. Sushko. 2015. "Dominance of interface chemistry over the bulk properties in determining the electronic structure of epitaxial metal/perovskite oxide heterojunctions." Chemistry of Materials 27, no. 11:4093-4098. PNNL-SA-108999. doi:10.1021/acs.chemmater.5b01118
• Droubay T.C., L. Kong, S.A. Chambers, and W.P. Hess. 2015. "Work Function Reduction by BaO: Growth of Crystalline Barium Oxide on Ag(001) and Ag(111) Surfaces." Surface Science 632. PNNL-SA-102305. doi:10.1016/j.susc.2014.07.010
• Ilton E.S., T.C. Droubay, A.M. Chaka, L. Kovarik, T. Varga, B.W. Arey, and S.N. Kerisit. 2015. "Epitaxial single-crystal thin films of MnxTi1-xO2-d grown on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory." Surface Science 632. PNNL-SA-102453. doi:10.1016/j.susc.2014.10.013
• Kong L., A.G. Joly, T.C. Droubay, and W.P. Hess. 2015. "Quantum Efficiency Enhancement in CsI/Metal Photocathodes." Chemical Physics Letters 621. PNNL-SA-107505. doi:10.1016/j.cplett.2015.01.010
• Moghadam M.J., K. Ahmadi-Majlan, X. Shen, T.C. Droubay, M.E. Bowden, M. Chrysler, and D. Su, et al. 2015. "Band-Gap Engineering at a Semiconductor-Crystalline Oxide Interface." Advanced Materials Interfaces 2, no. 4:Art No. 1400497. PNNL-SA-106514. doi:10.1002/admi.201400497
• Varga T., T.C. Droubay, M.E. Bowden, L. Kovarik, D. Hu, and S.A. Chambers. 2015. "Strain-dependence Of The Structure And Ferroic Properties Of Epitaxial NiTiO3 Thin Films Grown On Different Substrates." Advances in Condensed Matter Physics 2015. PNNL-SA-110090. doi:10.1155/2015/493045
• Varga T., T.C. Droubay, M.E. Bowden, S.A. Stephens, S. Manandhar, V. Shutthanandan, and R.J. Colby, et al. 2015. "Strain-dependence Of The Structure And Ferroic Properties Of Epitaxial Ni-1 (-) Ti-x(1) (-) O-y(3) Thin Films Grown On Sapphire Substrates." Thin Solid Films 578. PNNL-SA-106024. doi:10.1016/j.tsf.2015.02.016

2014

• Cui J., J. Choi, G. Li, E. Polikarpov, J.T. Darsell, N.R. Overman, and M.J. Olszta, et al. 2014. "Thermal Stability of MnBi Magnetic Materials." Journal of Physics: Condensed Matter 26, no. 6:Article No. 064212. PNNL-SA-97263. doi:10.1088/0953-8984/26/6/064212
• Droubay T.C., S.A. Chambers, A.G. Joly, W.P. Hess, K. Nemeth, K.C. Harkay, and L. Spentzouris. 2014. "Metal-Insulator Photocathode Heterojunction for Directed Electron Emission." Physical Review Letters 112, no. 6:067601(5). PNNL-SA-97936. doi:10.1103/PhysRevLett.112.067601
• Du Y., T.C. Droubay, A.V. Liyu, G. Li, and S.A. Chambers. 2014. "Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy." Applied Physics Letters 104, no. 16:Article No. 163110. PNNL-SA-101564. doi:10.1063/1.4873544
• Kerisit S.N., A.M. Chaka, T.C. Droubay, and E.S. Ilton. 2014. "Shell Model for Atomistic Simulation of Lithium Diffusion in Mixed Mn/Ti Oxides." Journal of Physical Chemistry C 118, no. 42:24231-24239. PNNL-SA-102922. doi:10.1021/jp506025k
• Kong L., A.G. Joly, T.C. Droubay, Y. Gong, and W.P. Hess. 2014. "Enhanced Quantum Efficiency From Hybrid Cesium Halide/Copper Photocathode." Applied Physics Letters 104, no. 17:Article No. 171106. PNNL-SA-101664. doi:10.1063/1.4874339

2013

• He W., S. VilayurGanapathy, A.G. Joly, T.C. Droubay, S.A. Chambers, J.R. Maldonado, and W.P. Hess. 2013. "Comparison of CsBr and KBr coated Cu photocathodes: Effects of laser irradiation and work function changes." Applied Physics Letters 102, no. 7:Article No. 071604. PNNL-SA-92864. doi:10.1063/1.4793214
• 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
• Look D.C., T.C. Droubay, and S.A. Chambers. 2013. "Optical/electrical correlations in ZnO: the plasmonic resonance phase diagram." Physica Status Solidi B, Basic Research 250, no. 10:2118-2121. PNNL-SA-92181. doi:10.1002/pssb.201200968
• McCloy J.S., W. Jiang, T.C. Droubay, T. Varga, L. Kovarik, J.A. Sundararajan, and M. Kaur, et al. 2013. "Ion irradiation of Fe-Fe oxide core-shell nanocluster films: Effect of interface on stability of magnetic properties." Journal of Applied Physics 114, no. 8:083903:1-9. PNNL-SA-95858. doi:10.1063/1.4818309
• Qiao L., H.Y. Xiao, S.M. Heald, M.E. Bowden, T. Varga, G.J. Exarhos, and M.D. Biegalski, et al. 2013. "The impact of crystal symmetry on the electronic structure and functional properties of complex lanthanum chromium oxides." Journal of Materials Chemistry C 1, no. 30:4527-4535. PNNL-SA-94824. doi:10.1039/C3TC30883A
• Varga T., T.C. Droubay, M.E. Bowden, R.J. Colby, S. Manandhar, V. Shutthanandan, and D. Hu, et al. 2013. "Coexistence of Weak Ferromagnetism and Polar Lattice Distortion in Epitaxial NiTiO3 thin films of the LiNbO3-Type Structure." Journal of Vacuum Science and Technology B--Microelectronics and Nanometer Structures 31, no. 3:Article No. 030603. PNNL-SA-92833. doi:10.1116/1.4801664

2012

• Chambers S.A., T.C. Droubay, C. Capan, and G. Sun. 2012. "Unintentional F doping of SrTiO3(001) etched in HF acid-structure and electronic properties." Surface Science 606, no. 3-4:554-558. PNNL-SA-83140. doi:10.1016/j.susc.2011.11.029
• 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
• Look D.C., T.C. Droubay, and S.A. Chambers. 2012. "Stable highly conductive ZnO via reduction of Zn vacancies." Applied Physics Letters 101, no. 10:Article No. 102101. PNNL-SA-89053. doi:10.1063/1.4748869
• Varga T., T.C. Droubay, M.E. Bowden, P. Nachimuthu, V. Shutthanandan, T.B. Bolin, and W.A. Shelton, et al. 2012. "Epitaxial growth of NiTiO3 with a distorted ilmenite structure." Thin Solid Films 520, no. 17:5534-5541. PNNL-SA-83110. doi:10.1016/j.tsf.2012.04.060
• Warner C.L., W. Chouyyok, K.E. Mackie, D. Neiner, L. Saraf, T.C. Droubay, and M.G. Warner, et al. 2012. "Manganese Doping of Magnetic Iron Oxide Nanoparticles: Tailoring Surface Reactivity for a Regenerable Heavy Metal Sorbent." Langmuir 28, no. 8:3931-3937. PNNL-SA-81002. doi:10.1021/la2042235

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
• Droubay T.C., C.I. Pearce, E.S. Ilton, M.H. Engelhard, W. Jiang, S.M. Heald, and E. Arenholz, et al. 2011. "Epitaxial Fe3-xTixO4 films from magnetite to ulvöspinel by pulsed laser deposition." Physical Review. B, Condensed Matter 84, no. 12:Article No. 125443. PNNL-SA-78052. doi:10.1103/PhysRevB.84.125443
• 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
• Look D., T.C. Droubay, J.S. McCloy, Z. Zhu, and S.A. Chambers. 2011. "Ga-doped ZnO grown by pulsed laser deposition in H2: the roles of Ga and H." Journal of Vacuum Science and Technology A--Vacuum, Surfaces and Films 29, no. 3:Article No.: 03A102. PNNL-SA-74572. doi:10.1116/1.3523296
• McCloy J.S., R.K. Kukkadapu, J.V. Crum, B.R. Johnson, and T.C. Droubay. 2011. "Size Effects on Gamma Radiation Response of Magnetic Properties of Barium Hexaferrite Powders." Journal of Applied Physics 110, no. 11:Article No. 113912. PNNL-SA-80909. doi:10.1063/1.3665769
• 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
• 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

• Baer D.R., M.H. Engelhard, A.S. Lea, P. Nachimuthu, T.C. Droubay, J. Kim, and B. Lee, et al. 2010. "Comparison of the Sputter Rates of Oxide Films Relative to the Sputter Rate of SiO2." Journal of Vacuum Science and Technology A--Vacuum, Surfaces and Films 28, no. 5:1060-1072. PNNL-SA-67505. doi:10.1116/1.3456123
• Chambers S.A., M.H. Engelhard, V. Shutthanandan, Z. Zhu, T.C. Droubay, L. Qiao, and P.V. Sushko, et al. 2010. "Instability, intermixing and electronic structure at the epitaxial LaAlO3/SrTiO3(001) heterojunction." Surface Science Reports 65, no. 10-12:317-352. PNNL-SA-73191. doi:10.1016/j.surfrep.2010.09.001
• 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.
• Johs A., L. Shi, T.C. Droubay, J.F. Ankner, and L. Liang. 2010. "Characterization of the Decaheme c-Type Cytochrome OmcA in Solution and on Hematite Surfaces by Small Angle X-Ray Scattering and Neutron Reflectometry." Biophysical Journal 98, no. 12:3035-3043. PNNL-SA-73702.
• 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
• Qiao L., T.C. Droubay, V. Shutthanandan, Z. Zhu, P.V. Sushko, and S.A. Chambers. 2010. "Thermodynamic Instability at the Stoichiometric LaAlO3/SrTiO3(001) Interface." Journal of Physics: Condensed Matter 22, no. 31:Art. No. 312201. PNNL-SA-73534. doi:10.1088/0953-8984/22/31/312201
• Warner C.L., S. Addleman, A.D. Cinson, T.C. Droubay, M.H. Engelhard, M.A. Nash, and W. Yantasee, et al. 2010. "High-Performance, Superparamagnetic, Nanoparticle-Based Heavy Metal Sorbents for Removal of Contaminants from Natural Waters." ChemSusChem 3, no. 6:749-757. PNNL-SA-70116. doi:10.1002/cssc.201000027

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.
• Lower B.H., R. Yongsunthon, L. Shi, L. Wildling, L. Wildling, H.J. Gruber, and N.S. Wigginton, et al. 2009. "Antibody recognition force microscopy shows that outer membrane cytochromes OmcA and MtrC are expressed on the exterior surface of Shewanella oneidensis MR-1." Applied and Environmental Microbiology 75, no. 9:2931-2935. PNNL-SA-61844.
• Warner M.G., C.L. Warner, R.S. Addleman, T.C. Droubay, M.H. Engelhard, J.D. Davidson, and A.D. Cinson, et al. 2009. "Synthesis of Functionalized Superparamagnetic Iron Oxide Nanoparticles from a Common Precursor and their Application as Heavy Metal and Actinide Sorbents." In Abstracts of Papers of the 237th ACS National Meeting, March 22-26, 2009, Salt Lake City, Utah, COLL-465. Washington Dc:American Chemical Society. PNNL-SA-65452.

2008

• Eggleston C.M., J. Voros, L. Shi, B.H. Lower, T.C. Droubay, and P.J. Colberg. 2008. "Binding and Direct Electrochemistry of OmcA, an Outer-Membrane Cytochrome from an Iron Reducing Bacterium, with Oxide Electrodes: A Candidate Biofuel Cell System." Inorganica Chimica Acta 361, no. 3:769-777. PNNL-SA-56726. doi:10.1016/j.ica.2007.07.015
• 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.

2007

• Cai M., S.C. Langford, J.T. Dickinson, G. Xiong, T.C. Droubay, A.G. Joly, and K.M. Beck, et al. 2007. "An In Situ Study of the Martensitic Transformation in Shape Memory Alloys Using Photoemission Electron Microscopy." Journal of Nuclear Materials 361, no. 2-3:306-312. PNNL-SA-49612. doi:10.1016/j.jnucmat.2006.12.008
• Cai M., S.C. Langford, M.J. Wu, W.M. Huang, G. Xiong, T.C. Droubay, and A.G. Joly, et al. 2007. "Study of Martensitic Phase transformation in a NiTiCu Thin Film Shape Memory Alloy Using Photoelectron Emission Microscopy." Advanced Functional Materials 17, no. 1:161-167. PNNL-SA-49610. doi:10.1002/adfm.200600611
• Droubay T.C., K.M. Rosso, S.M. Heald, D.E. Mccready, C.M. Wang, and S.A. Chambers. 2007. "Structure, Magnetism and Conductivity in Epitaxial Ti-doped ?-Fe2O3 Hematite: Experiment and density functional theory calculations." Physical Review. B, Condensed Matter and Materials Physics 75, no. 10. PNNL-SA-48675. doi:10.1103/PhysRevB.75.104412
• Lower B.H., L. Shi, R. Yongsunthon, T.C. Droubay, D.E. Mccready, and S. Lower. 2007. "Specific Bonds between an Iron Oxide Surface and Outer Membrane Cytochromes MtrC and OmcA from Shewanella oneidensis MR-1." Journal of Bacteriology 189, no. 13:4944-4952. PNNL-SA-51713. doi:10.1128/JB.01518-06
• Shao R., C.M. Wang, D.E. McCready, T.C. Droubay, and S.A. Chambers. 2007. "Growth and structure of MBE grown TiO2 anatase films with rutile nano-crystallites." Surface Science 601, no. 6:1582-1589. PNNL-SA-52119. doi:10.1016/j.susc.2007.01.039
• Xiong G., R. Shao, T.C. Droubay, A.G. Joly, K.M. Beck, S.A. Chambers, and W.P. Hess. 2007. "Photoemission Electron Microscopy of TiO2 Anatase Films Embedded with Rutile Nanocrystals." Advanced Functional Materials 17, no. 13:2133-2138. PNNL-SA-53255. doi:10.1002/adfm.200700146

2006

• Chambers S.A., T.C. Droubay, C.M. Wang, K.M. Rosso, S.M. Heald, S.A. Schwartz, and K.R. Kittilstved, et al. 2006. "Ferromagnetism in Oxide Semiconductors." Materials Today 9, no. 11:28-35. PNNL-SA-50589.
• 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, S.M. Heald, M.H. Engelhard, D.E. McCready, and S.A. Chambers, et al. 2006. "Synthesis of Room-Temperature Ferromagnetic Cr-doped TiO2(110) Rutile Single Crystals using Ion Implantation." Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms 242, no. 1-2:198-200. PNNL-SA-43506. doi:10.1016/j.nimb.2005.08.149
• 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

• Cai M., S.C. Langford, T. Dickinson, W.M. Huang, Q. He, T.C. Droubay, and D.R. Baer. 2005. "Study of Martensitic Transformation in a CuZnAl Shape Memory Alloy using Photoemission." In Proceedings of the International Conference on Mechanical Engineering and Mechanics (ICMEM2005), edited by RC Batra and L Qian, 1123-1127. Monmouth Junction, New Jersey:Science Press. PNNL-SA-45741.
• 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.
• Droubay T.C., S.M. Heald, V. Shutthanandan, S. Thevuthasan, S.A. Chambers, and J. Osterwalder. 2005. "Cr-doped TiO2 Anatase- A Ferromagnetic Insulator." Journal of Applied Physics 97. PNNL-SA-42652.
• Heald S.M., S.A. Chambers, and T.C. Droubay. 2005. "XAFS study of CoxTi1-xO2-x-anatase." Physica Scripta T115. PNNL-14575. doi:10.1238/Physica.Topical.115a00597
• Heald S.M., S.A. Chambers, and T.C. Droubay. 2005. "XAFS Study of Epitaxial CoxTi1-xO2-x Anatase." In 12th International Conference on X-ray Absorption FIne Structure held in Malmo, Sweden, June, 2003, edited by N. Martensson, 597-599. Stockholm:Royal Swedish Academy of Sciences. PNNL-SA-38914.
• Jaffe J.E., T.C. Droubay, and S.A. Chambers. 2005. "Oxygen Vacancies and Ferromagnetism in CoxTi1-xO2-x-y." Journal of Applied Physics 97, no. 7:073908 (6 p.). PNNL-SA-42498.
• 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.
• Sasahara A., T.C. Droubay, S.A. Chambers, H. Uetsuka, and H. Onishi. 2005. "Topography of Anatase TiO2 Film Synthesized on LaAlO3(001)." Nanotechnology 16, no. 3:S18-S21. PNNL-SA-43039.
• Wang C.M., V. Shutthanandan, S. Thevuthasan, T.C. Droubay, and S.A. Chambers. 2005. "Microstructure of Co-doped TiO2 (110) Rutile by Ion Implantation." Journal of Applied Physics 97, no. 7:99-104. PNNL-SA-42989.

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
• Kim Y.J., S. Thevuthasan, T.C. Droubay, A.S. Lea, C.M. Wang, V. Shutthanandan, and S.A. Chambers, et al. 2004. "Growth and Properties of molecular beam epitaxially grown ferromagnetic Fe-doped TiO2 rutile films on TiO2." Applied Physics Letters 84, no. 18:3531-3533. PNNL-SA-40048.
• 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

• Chambers S.A., S.M. Heald, and T.C. Droubay. 2003. "Local Co Structure in Epitaxial Cox Ti1-xO2-x Anatase." Physical Review. B, Condensed Matter and Materials Physics 67, no. 10:22-25, art. no. 100401. PNNL-SA-37018.
• Chambers S.A., T.C. Droubay, C.M. Wang, A.S. Lea, R. Farrow, L. Folks, and V. Deline, et al. 2003. "Clusters and Magnetism in Epitaxial Co-doped TiO2 Anatase." Applied Physics Letters 82, no. 8:1257-1259. PNNL-SA-37993.
• 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.

2002

• Altman E.I., T.C. Droubay, and S.A. Chambers. 2002. "Growth of MoO3 films by oxygen plasma assisted molecular beam epitaxy." Thin Solid Films 414, no. 2:205-215. PNNL-SA-37910.
• Chambers S.A., C.M. Wang, S. Thevuthasan, T.C. Droubay, D.E. McCready, A.S. Lea, and V. Shutthanandan, et al. 2002. "Epitaxial Growth and Properties of MBE Grown Ferromagnetic Co-doped TiO2 Anatase Films on SrTiO3(001) and LaAlO3(001)." Thin Solid Films 418, no. 2:197-210. PNNL-SA-35981.
• Chambers S.A., T.C. Droubay, D.R. Jennison, and T.K. Mattsson. 2002. "Laminar Growth of Ultrathin Metal Films on Metal Oxides: Co on Hydroxylated alpha-Al2O3(0001)." Science 297, no. 5582:827-831. PNNL-SA-35870.

2001

• Chambers S.A., and T.C. Droubay. 2001. "The Role of Oxide Ionicity in Electronic Screening at Oxide/Metal Interfaces." Physical Review. B, Condensed Matter 64. PNNL-SA-34328.
• Droubay T.C., and S.A. Chambers. 2001. "Surface Sensitive Fe 2p Photoemission Spectra for alpha-Fe2O3 (0001) - The Influence of Symmetry and Crystal-Field Strength." Physical Review. B, Condensed Matter 64, no. 20:205414-205420. PNNL-SA-43517.