BACKGROUND Dr. Leonard Brillson leads an interdisciplinary research effort in Solid State Electronics at The Ohio State University. Dr. Brillson holds a joint appointment between the Department of Electrical & Computer Engineering, the Department of Physics, and the Center for Materials Research.  Professor Brillson established his laboratory at The Ohio State University for research in the properties of advanced electronic material thin films and interfaces, centered on single crystal complex oxides, semiconductors, and polycrystalline photovoltaics at the nanoscale. Current research emphasizes the electronic and chemical structure of state-of-the-art  ferroelectrics, ferromagnets, and multiferroics in combination with wide gap semiconductors, especially the influence of local compositional structure and defects on electromagnetic properties, Schottky barrier formation, and heterojunction band offsets. A renaissance has occurred in the crystalline growth of these electronic materials, and they are having a major impact on environmentally-friendly energy creation, next generation solid state lighting, ultrahigh speed communication, and computing. A  new initiative in bioelectronic materials and interfaces aims to produce compact, mass-producible sensors for use in sensitive immunological and pathogen detection. Prof. Brillson's group makes use of  a wide range of ultrahigh vacuum surface and interface science research facilities, including quantum-scale,UHV low energy electron-excited nanoscale luminescence, Auger electron, and secondary ion mass spectroscopies, electron microscopy, as well as clean room facilities for nanostructure fabrication and processing. This group also has strong interdisciplinary interactions with an extensive electronic materials community on campus.  Prof. Brillson is promoting interdisciplinary programs in electronic materials across campus through the Center for Materials Research.

Professor Leonard J. Brillson

Brillson formerly directed Xerox Corporation's Materials Research Laboratory and had responsibility for Xerox's long-range physical science and technology programs at the company's research headquarters in Rochester, N.Y. He is a Fellow of the Institute of Electrical and Electronics Engineers (IEEE), a Fellow of the AVS Science & Technology Society (AVS), a Fellow of the American Physical Society (APS), a Fellow of the American Association for the Advancement of Science (AAAS), and a former Governing Board member of the American Institute of Physics. He has served on the board of editors for numerous technical journals, and has more than 280 professional publications including technical articles, invited reviews, monographs and books. Selected publications are shown below. He was recently awarded the 2006 Gaede-Langmuir Award from the AVS Science & Technology Society for "demonstration of the fundamental importance of semiconductor interfacial bonding, metallurgical reactions, and defect formation upon solid state material and device properties." In 2007, he was inducted into the National Honor Society of Phi Kappa Phi.

Dr. Brillson received his A.B. degree in physics from Princeton University and his Ph.D. in physics from the University of Pennsylvania.

Professor Leonard J. Brillson

RESEARCH INTERESTS Electronic materials, semiconductor heterojunction and metal contacts, nanoelectronics, optoelectronics, solar cells, surface science, defects in crystalline semiconductors and complex oxides, materials characterization and processing. Dr. Brillson has a broad research program in the structure and properties of electronic materials' thin films and interfaces, emphasizing compound semiconductors for high speed microelectronic and optoelectronic device structures, wide band gap semiconductors for sensor and display applications, ferroelectric and multiferroic oxides for spintronic and ultrahigh frequency communications, high efficiency,polycrystalline solar cells for space applications, and thin film dielectrics for ultrasmall transistor gate structures. Understanding and control of such interfaces focuses on atomic-scale reaction and diffusion processes to control formation of localized electronic states, dipoles, Schottky barrier heights, and heterojunction band offsets. Experimental studies of electronic, chemical, and geometrical structure utilizing UV, X-ray, and soft x-ray photoemission spectroscopies, low energy (spatially-localized) cathodoluminescence and photoluminescence "buried interface" spectroscopies, Auger electron spectroscopy (AES) with sputter depth profiling, low energy electron diffraction (LEED), scanning tunneling microscopy (STM), Kelvin probe surface photovoltage spectroscopy, conventional device transport techniques, and in-situ chemical processing via directed energy beams. The scaling down of electronic device dimensions into the nanometer-scale regime emphasizes the need for first-principles, atomic-scale control of interface properties. Recent advances include the discovery of heterojunction band offset variations with local atomic movements near interfaces and the role of localized trap states in controlling charge transfer across nanoparticle contacts. Complex oxide research planned for 2007 include acquisition of a molecular beam epitaxy system for thin film heterojunction growth and atomic-scale control of their chemical and electronic properties.

Dr. Brillson's offices are located at:

His primary mailing address is:

• H.L. Mosbacker, C. Zgrabik, M.J. Hetzer, A. Swain, D.C. Look, G. Cantwell, J. Zhang, J.J. Song, and L.J. Brillson, "Thermally Driven Defect Formation and Blocking Layers at Metal-ZnO Interfaces," Applied Physics Letters 91, 072102 (2007).

• L.J. Brillson, H.L. Mosbacker, M.J. Hetzer, Y. Strzhemechny, G.H. Jessen, D.C. Look, G. Cantwell, J. Zhang, and J.J. Song, "Dominant Effect of Near-Interface Native Point Defects on ZnO Schottky Barriers," Applied Physics Letters 90102116 (2007).
  

• D.E. Walker, Jr., R.C. Fitch, J.K. Gillespie, G.H. Jess, P. Cassity, J. Breedlove, and L.J. Brillson, “Controlled Gate Surface Processing of AlGaN/GaN High Electron Mobility Transistors,” Applied Physics Letters 89, 183523 (2006).

• H.L. Mosbacker, Y.M. Strzhemechny, B.D. White, P.E. Smith, D.C. Look, D.C. Reynolds, C.W. Litton, and L.J. Brillson, “Role of Near-Surface States in Ohmic-Schottky Conversion of Au Contacts to    ZnO,” Applied Physics Letters 87, 012102 (2005).

• S.P.Tumakha, D.J. Ewing, L.M. Porter, Q.Wahab, X.Ma, T.S. Sudharshan, and L.J. Brillson, “Defect Driven Inhomogeneities in Ni/4H-SiC Schottky Barriers,” Applied Physics Letters  87, 242106 (2005). 

• M. Gao, Y. Lin, S.T. Bradley, S.A. Ringel, J. Hwang, W.J. Schaff, and L.J. Brillson, “Spontaneous Compositional Superlattice and Band Gap Reduction in Si-doped AlxGa1-xN Epilayers,” Applied Physics Letters 87, 191106 (2005).

• S. C. Lee, M. T. Keener, D. R. Tokachichu, B.Bhushan, P. D. Barnes, B. R. Cipriany, M. Gao, and L. J. Brillson, “Protein Binding on Thermally Grown Silicon Dioxide,”  Journal of Vacuum Science and Technology B23, 1856 (2005); Virtual J. Biolog. Phys. 10 (4) (2005).

• M. Hetzer, Y.M. Strzhemechny, L.J. Brillson, M.A. Contreras, and A. Zunger, “Direct Observation of Copper Depletion and Potential Changes at Copper Indium Gallium Diselenide Grain Boundaries,”  Applied Physics Letters 86, 162105 (2005).

• Y.M. Strzhemechny, H.L. Mosbacker, D.C. Look, D.C. Reynolds, C.W. Litton, N.Y.Garces, NC. Giles, L.E. Halliburton, S. Niki, and L.J. Brillson, “Remote Hydrogen Plasma Doping of Single Crystal ZnO,” Applied Physics Letters 84, 2545-2547 (2004).
  

• S.T. Bradley,  L.J. Brillson, J. Hwang, and W.J. Schaff, “Surface Cleaning and Annealing Effects on Ni/AlGaN Interface Atomic Composition and Schottky Barrier Height,” Applied Physics Letter 85, 1368-1370 (2004).

• G.H. Jessen, R.C. Fitch, J.K. Gillespie, G.D. Via, B.D. White, S.T. Bradley, D.E. Walker, Jr. and L.J. Brillson, "Effects of Deep-Level Defects on Ohmic Contact and Frequency Performance of AlGaN/GaN High-Electron-Mobility Transistors," Applied Physics Letters, 83, 485 (2003).

• L.J. Brillson, S. Tumakha, G.H. Jessen, R.S. Okojie, M. Zhang, and P. Pirouz, "Thermal and Doping Dependence of 4H-SiC Polytype Transformation," Applied Physics Letters 81, 2785 (2002).

• S.H. Goss, X.L. Sun, L.J. Brillson, D.C.Look, and R.J. Molnar, "Microcathodoluminescence Spectroscopy of Impurity Doping at Gallium Nitride/Sapphire Interfaces," Applied Physics Letters 78, 3630 (2001).

• L. J. Brillson, S. Silence, "Patterned Conducting Elements for Development Subsystems", U.S. Patent No. 5,643,706, issued 7/1/97.

• L.J. Brillson, "Multi-Color Photosensitive Element with Heterojunctions", U.S. Patent No. 5,138,416, issued 8/18/92.
  
  
• L.J. Brillson, "Surfaces and Interfaces: Atomic-Scale Structure, Band Bending and Band Offsets," in Handbook on Semiconductors, Volume 1, ed. P.T. Landsberg (North-Holland, Amsterdam, 1992), ch.7, pp. 281-417.
• S. Chang, L.J. Brillson, Y.J. Kime, D.S. Rioux, D. Pettit, and J.M. Woodall, "Orientation-Dependent Chemistry and Schottky Barrier Formation at Metal- GaAs Interfaces," Physical Review Letters 64, 2551 (1990).
• L.J. Brillson, "The Structure and Properties of Metal-Semiconductor Interfaces," Surface Science Reports 2, 123 (1982).
• J. Schafer, A.P. Young, L.J. Brillson, H. Niimi, and G. Lucovsky, "Depth-Dependent Spectroscopic Defect Characterization of The Interface Between Plasma-Deposited SiO₂ and Silicon," Applied Physics Letters 73 ,791 (1998).