Education

Ph.D. (1991), Physics, Drexel University
M.S. (1987), Physics, Drexel University
B.S. (1985), Mechanical Engineering, Tennessee Tech University

Associate Professor (2006 – Present), Department of Physics, Texas State University
Associate Professor (2000 – 2006), Department of Physics, University of New Orleans
Assistant Professor (1996 – 2000), Department of Physics, University of New Orleans
Visiting Professor (1995 - 1996), Department of Physics, Applied Physics, & Astronomy, Rensselaer Polytechnic Institute
Postdoc (1993 - 1995), Department of Physics, Applied Physics, & Astronomy, Rensselaer Polytechnic Institute
Postdoc (1991 - 1993), Lehrstuhl für Physikalische Chemie I & Institut für Experimentalphysik IV, Ruhr-Universität Bochum

Surface/Interface Science: The performance of a solid-state device is often affected by the electrical, magnetic, and chemical properties of the surfaces and interfaces of the constituent materials of the device.  For instance, the device performance of field effect transistors and metal/semiconductor Schottky diodes is usually governed by interface states.  Materials that exhibit ferromagnetic ordering in the bulk may have a drastically different Curie temperature in the surface region or may exhibit no ferromagnetic ordering at all.  Surface reconstructions are common for most semiconducting materials, and these reconstructions are often accompanied by a change in the band gap or even a conversion to metallic behavior at the surface.  These are just a few of the examples of where the surface or interface properties need to be considered to properly understand the performance of solid-state devices.

Graphene-based Nanoelectronic Devices: Graphene is a single atomic layer of graphite.  It has many unique properties that are of particular interest for the development of nanoscale electronic devices.  It is a semi-metal whose charge carrier density can be continuously tuned from n-type to p-type by applying an electric field; it has a linear energy-momentum dispersion in the vicinity of the Dirac point; its mobility is higher than all of the known semiconductors.  However, one of the primary issues that must be addressed before nanoscale electronic devices can be routinely fabricated is the development of methods for growing large-scale, high-quality, single-layer graphene sheets on semiconducting substrates.  One of the most popular methods of growing graphene is the precipitation of graphene layers at the surface of SiC at high temperatures in UHV.  Because of the high cost of device quality SiC wafers (~$5k per 2” wafer) and the tendency to form graphene bi-layers instead of single-layers on SiC, our group has pursued the growth of graphene by the thermal reduction of exfoliated graphene oxide sheets.

Surface Electronic and Magnetic Structure of Half-metallic Oxides: Half-metallic ferromagnets are solids whose conduction electrons undergo magnetic ordering with a spin polarization of 100% at the Fermi level.  Since the conventional ferromagnets typically have spin polarizations of less than 50%, the performance of devices such as GMR sensors or TMR spin valves should increase dramatically if the conventional ferromagnetic materials are replaced with half-metallic materials.  However, devices based on half-metallic materials almost always show a decrease in performance instead of an enhancement.  One possible source of the poor performance of devices based on half-metals is a deviation from metallic or ferromagnetic behavior at the interfaces within these devices.  Therefore, our research involves measuring the surface structure and corresponding electronic and magnetic properties of half metallic oxides such as chromium dioxide.

Stability of Polar Oxide Surfaces: For ionic materials, surface instabilities result from terminating a crystal at a polar surface.  Most often, these polar surfaces will facet into surface structures with non-polar terminations.  However, there are some instances, such as the p(2x2) octopolar reconstruction of NiO(111), where simple surface reconstructions can stabilize the surface.  Our research focuses on developing methods for growing materials with polar surface terminations that have simple reconstructions and characterizing the corresponding electrical and chemical properties of these unique surface terminations.

Growth and Characterization of Self-Assembled Monolayers: SAMs are molecular films that self-terminate at a single monolayer and usually show some order.  Molecular electronics devices can be formed via the growth of semiconducting and insulating layers of SAMs.  Most groups grow SAMs on Au substrates because of its inertness.  However, if one is to couple molecular electronics devices with conventional Si-based electronics, metal substrates other than Au should be used since Au diffuses into Si, adversely affecting its semiconducting properties.  Our research focuses on examining the growth morphology and resulting electrical properties of SAMs on Pt, Ag, and Cu substrates, which are all more “Si-friendly” metals.

Current Students

Daniel R. Borst, Angle-Resolved Photemission Study of Epitaxial CrO₂ Films, M.S. in Physics, University of New Orleans (2006)

Greg Gothard, Analysis of Core Level Photoelectron Spectroscopy Data by Deconvolution, M.S. in Applied Physics, University of New Orleans (2006)

Timothy M. Sweeney, Photoemission and Low Energy Electron Diffraction Study of Dodecanethiol on Pt(111) and Pt(100), M.S. in Physics, University of New Orleans (2004)

Sten N. Thornburg, Measurement of the Dependence of Bulk Defects on the Reactivity of the TiO₂(110) Surface, M.S. in Applied Physics, University of New Orleans (2003)

James M. Burst, Photoemission Study of Dodecanethiol on Au(111) and Ag(111), M.S. in Physics, University of New Orleans (2003)

Christina K. Davis, Comparative Analysis of the Clean and Oxygen Dosed Ag(100) Surfaces Using Low Energy Electron Diffraction, M.S. in Physics, University of New Orleans (2001)

Brad M. Guillory, Design and Construction of a Thin-Film Deposition System for Growth and Characterization of Ag-Si Schottky Diodes, B.S. in Physics with Honors, University of New Orleans (2001)

Patricia S. Robbert, Photoemission Study of the Novel Electronic Properties of Ultra-thin Chromium Oxide Films Grown on Pt(111), M.S. in Applied Physics, University of New Orleans (1999)

Marc M. Howard, Growth and Characterization of Epitaxial Metal-oxide Films: Tantalum Oxide/Ag(100) and NiO(100)/Ag(100), M.S. in Physics, University of New Orleans (1999)

Bryan R. King, Photoemission Study of the Polar NiO(111) Surface Grown on Au(111), M.S. in Physics, University of New Orleans (1998)

Vincent P. LaBella, Hot Electron Transport and Surface Morphology Studies of MBE Grown Pt/CaF₂/Si(111) Structures, Ph.D. in Physics, Rensselaer Polytechnic Institute (1998)

Book Chapters

The Growth and Structure of Epitaxial Metal-oxide/Metal Interfaces, C. A. Ventrice, Jr. and H. Geisler, in Heteroepitaxy: Thin Film Systems, edited by W. K. Liu and M. B. Santos, pp. 167-210 (World Scientific Publishers, Singapore, 1999).

Ballistic Electron Emission Microscopy, N. J. DiNardo and C. A. Ventrice, Jr., in Handbook of Microscopy, Methods II, edited by S. Amelinckx, D. Van Dyck, J. Van Landuyt, and G. Van Tendeloo, pp. 856-882 (VCH, Weinheim, 1997).

Journal Articles

Chemical Analysis of Graphene Oxide Films After Heat and Chemical Treatments by X-ray Photoelectron and Micro-Raman Spectroscopy, D. Yang, A. Velamakanni, G. Bozoklu, A. Park, M. Stoller, R. D. Piner, S. Stankovich, I. Jung, D. A. Field, C. A. Ventrice, Jr., and R. S. Ruoff, Carbon, Submitted: May 2008.  (in press)

Are the surfaces of CrO₂ metallic?, C. A. Ventrice Jr., D. R. Borst, H. Geisler, J. van Ek, Y B Losovyj, P. S. Robbert, U. Diebold, J. A. Rodriguez, G. X. Miao, and A. Gupta, Journal of Physics: Condensed Matter, Vol. 19, MS #315207, pp. 1-18 (2007).

Magnetoresistive Multilayers Deposited on the AAO Membranes, L. M.  Malkinski, A. Chalastaras, A. Vovk. J-S. Jung, E.-M Kim, J.-H Jum, C. A. Ventrice. Jr., J. Magn. Magn. Mater., Vol. 286, pp. 108-112 (2005).

 GMR Multilayers on a New Embossed Surface, A. Chalastaras, L. M. Malkinski, J.-S. Jung, S.-L. Oh, J.-K. Lee, C. A. Ventrice, Jr., V. Golub, and G. Taylor, IEEE Transactions on Magnetics, Vol. 40, pp. 2257-2259 (2004).

 The Electronic Structure of Metal/Alkane Thiol Self-Assembled Monolayers/Metal Junctions for Magnetoelectronics Applications, Y. A. Ovchenkov, H. Geisler, J. M. Burst, S. N. Thornburg, C. A. Ventrice, Jr., C. Zhang, J. Redepenning, Y. Losovyj, L. Rosa, P. A. Dowben, and B. Doudin, Chemical Physics Letters, Vol. 381, pp. 7-13 (2003).

 The Adsorption of Chlorine on TiO₂(110) Studied with Scanning Tunneling Microscopy and Photoemission Spectroscopy, E. L. D. Hebenstreit, W. Hebenstreit, H. Geisler, C. A. Ventrice, D. A. Hite, P. T. Sprunger, and U. Diebold, Surface Science, Vol. 505, pp. 336-348 (2002).

 Sulfur on TiO₂(110) Studied with Resonant Photoemission, E. L. D. Hebenstreit, W. Hebenstreit, H. Geisler, S. N. Thornburg, C. A. Ventrice, Jr., D. A. Hite, P. T. Sprunger, and U. Diebold, Physical Review B, Vol. 64, MS #115418, pp. 1-11 (2001).

Bulk-defect Dependent Adsorption on a Metal Oxide Surface: S/TiO₂(110), E. L. D. Hebenstreit, W. Hebenstreit, H. Geisler, C. A. Ventrice, Jr., P. T. Sprunger, and U. Diebold, Surface Science Letters, Vol. 486, pp. L467-L474 (2001).

 Surface Morphology and Electronic Structure of Ni/Ag(100), D. A. Hite, O. Kizilkaya, P. T. Sprunger, M. M. Howard, C. A. Ventrice, Jr., H. Geisler, and D. M. Zehner, Journal of Vacuum Science and Technology A, Vol. 18, pp. 1950-1954 (2000).

 Measurement of Epitaxially Grown Pt/CaF₂/Si(111) Structures by Ballistic Electron Emission Microscopy and Scanning Tunneling Microscopy, V. P. LaBella, Y. Shusterman, L. J. Schowalter, and C. A. Ventrice, Jr., Journal of Vacuum Science and Technology A, Vol. 16, #3, pp. 1692-1696 (1998).

 Novel Electronic and Magnetic Properties of Ultrathin Chromium Oxide Films Grown on Pt(111), P. S. Robbert, H. Geisler, C. A. Ventrice, Jr., J. van Ek, S. Chaturvedi, J. A. Rodriguez, M. Kuhn, and U. Diebold, Journal of Vacuum Science and Technology A, Vol. 16, #3, pp. 990-995 (1998).

 Ballistic Electron Emission Microscopy Measurements of Epitaxially Grown Pt/CaF₂/Si(111) Structures, V. P. LaBella, C. A. Ventrice, Jr., and L. J. Schowalter, Applied Surface Science, Vol. 123/124, pp. 213-218 (1998).

 H₂S Adsorption of Chromium, Chromia, and Gold/chromia Surfaces: Photoemision Studies, J. A. Rodriguez, S. Chaturvedi, M. Kuhn, J. van Ek, U. Diebold, P. S. Robbert, H. Geisler, and C. A. Ventrice, Jr., Journal of Chemical Physics, Vol. 107, #21, pp. 9146-9156 (1997).

 Scanning Tunneling Microscopy and Ballistic Electron Emission Spectroscopy Studies of Molecular Beam Epitaxy Grown Pt/CaF₂/Si(111) Structures, V. P. LaBella, L. J. Schowalter, and C. A. Ventrice, Jr., Journal of Vacuum Science and Technology B, Vol. 15, #4, pp. 1191-1195 (1997).

 Design of a Scanning Tunneling Microscope for In-situ Topographic and Spectroscopic Measurements within a Commercial Molecular Beam Epitaxy Machine, C. A. Ventrice, Jr., V. P. LaBella, and L. J. Schowalter, Journal of Vacuum Science and Technology A, Vol. 15, # 3, pp. 830-835 (1997).

 Hot-electron Scattering at Au/Si(100) Schottky Interfaces Measured by Temperature Dependent Ballistic Electron Emission Microscopy, C. A. Ventrice, Jr., V. P. LaBella, G. Ramaswamy, H.-P. Yu, and L. J. Schowalter, Applied Surface Science , Vol. 104/105, pp. 274-281 (1996).

 Molecular Beam Epitaxy Growth of Thin CaF₂ Films on Vicinal Si(111) Surfaces, B. M. Kim, C. A. Ventrice, Jr., T. Mercer, R. Overney, and L. J. Schowalter, Applied Surface Science, Vol. 104/105, pp. 409-416 (1996).

 Measurement of Hot-electron Scattering Processes at Au/Si(100) Schottky Interfaces by Temperature Dependent Ballistic Electron Emission Microscopy, C. A. Ventrice, Jr., V. P. LaBella, G. Ramaswamy, H.-P. Yu, and L. J. Schowalter, Physical Review B, Vol. 53, # 7, pp. 3952-3959 (1996).

Rastertunnelmikroskopie an geordneten dünnen Oxidschichten: NiO(10)/Ag(100) und NiO(111)/Au(111), H. Neddermeyer, T. Bertrams, H. Hannemann, and C. A. Ventrice, Jr., Nova Acta Leopoldina, Vol. 73, pp. 51-61 (1995).

 Scanning Tunneling Microscopy on the Growth of Ordered NiO Layers on Au(111), H. Hannemann, C. A. Ventrice, Jr. , Th. Bertrams, A. Brodde, and H. Neddermeyer, Physica Status Solidi A-Applied Research, Vol. 146, pp. 289-297 (1994).

 Electronic and Geometric Structure of Adsorbates on Oxide Surfaces, D. Cappus, M. Menges, C. Xu, D. Ehrlich, B. Dillmann, C. A. Ventrice, Jr., J. Libuda, M. Bäumer, S. Wohlrab, F. Winkelmann, H. Kuhlenbeck, and H.-J. Freund, Journal of Electron Spectroscopy and Related Phenomena, Vol. 68, pp. 347-355 (1994).

Stable Reconstruction of the Polar (111) Surface of NiO on Au(111), C. A. Ventrice, Jr., Th. Bertrams, H. Hannemann, A. Brodde, and H. Neddermeyer, Physical Review B, Rapid Communications, Vol. 49, #8, pp. 5773-5776 (1994).

 STM of Manipulated Structures: Characterization of Metal Oxide Films, Th. Bertrams, A. Brodde, H. Hannemann, C. A. Ventrice, Jr., G. Wilhelmi, and H. Neddermeyer, Applied Surface Science, Vol. 75, pp. 125-132 (1994).

 Electronic and Geometric Structure of Ultrathin Alkali-Metal-GaAs(110) Interfaces, N. J. DiNardo, C. A. Ventrice, Jr., T. Maeda Wong, A. J. Smith, D. Heskett, A. B. McLean, W. R. Graham, and E. W. Plummer, Trends in Vacuum Science and Technology, Vol. 1 (1993).

 Hydroxyl Groups on Oxide Surfaces:  NiO(100), NiO(111), and Cr₂O₃(111), D. Cappus, C. Xu, D. Ehrlich, B. Dillmann, C. A. Ventrice, Jr. K. Al Shamery, H. Kuhlenbeck, and H. J. Freund, Chemical Physics, Vol. 177, pp. 533-546 (1993).

 Electronic Surface States of NiO(100), A. Freitag, V. Staemmler, D. Cappus, C. A. Ventrice, Jr., K. Al Shamery, H. Kuhlenbeck, and H.-J. Freund, Chemical Physics Letters, Vol. 210, #1, pp. 10-14 (1993).

 Adsorption and Reaction of Molecules on Surfaces of Metal-metaloxide Systems, H.-J. Freund, B. Dillmann, D. Ehrlich, M. Haßel, R. M. Jaeger, H. Kuhlenbeck, C. A. Ventrice, Jr., F. Winkelmann, S. Wohlrab, C. Xu, Th. Bertrams, A. Brodde, and H. Neddermeyer, Journal of Molecular Catalysis, Vol. 82, pp. 143-169 (1993).

 The K/GaAs(110) Interface: Initial Stages of Growth and the Semiconductor-to-metal Transition, C. A. Ventrice, Jr. and N. J. DiNardo, Physical Review B, Vol. 47, #11, pp. 6470-6479 (1993).

 Metallic to Nonmetallic Transition of Na Coadsorbed with CO₂ and H₂O on the Cr₂O₃(111)/Cr(110) Surface, C. A. Ventrice, Jr., D. Ehrlich,  E. L. Garfunkel, B. Dillmann, D. Heskett, and H.-J. Freund, Physical Review B, Rapid Communications, Vol. 46, #19, pp. 12892-12895 (1992).

 Point Contact Tunneling Study of Bi2Sr2CaCu2O8, M. H. Jiang, C. A. Ventrice, Jr., K. J. Scoles, S. Tyagi, N. J. DiNardo, and A. Rothwarf, Physica C, Vol. 183, pp. 39-50 (1991).

 Potassium-induced Unrelaxation of the GaAs(110) Surface, C. A. Ventrice, Jr. and N. J. DiNardo, Physical Review B, Rapid Communicatons, Vol. 43, #17, pp. 14313-14316 (1991).