Date: Thursday, Oct 8th
Presenter: Scott A. Chambers, Laboratory Fellow, Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory
Oxide film growth is thought to be an effective way to harness the wide range of physical properties exhibited by transition metal oxides and complex oxides for technological purposes. Epitaxial growth allows the greatest depth of understanding to be gained because of the highly crystalline nature of the films. The most popular epitaxial growth methods are pulsed laser deposition (PLD), molecular beam epitaxy (MBE), magnetron sputtering (MS) and chemical vapor deposition (CVD). Of these, PLD is the most widely used because it is easy, and it is commonly thought that laser ablation above some threshold power level results in stoichiometric transfer of material from target to substrate. In this lecture, I will show that this assumption is not well founded, at least for a few oxides of very high current interest. I will open by comparing and contrasting PLD and MBE as growth tools for crystalline oxides, and then discuss recent work on Co-doped ZnO/alpha-Al2O3(0001) and SrTiO3/LaAlO3(001). These two systems have been of extremely high interest for potential use in oxide spintronics and electronics. Detailed studies reveal that when grown in the on-axis geometry by PLD, the compositions and nanostructural environments of these materials differ considerably from what has been widely assumed in the literature.
Scott Chambers is a Laboratory Fellow and Technical Lead for the Epitaxial Oxides Group, as well as a Wiley Research Fellow in the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. He is also an Affiliate Professor of Chemistry and Materials Science and Engineering at the University of Washington. He holds an A.B. degree in chemistry/chemical physics from the University of California at San Diego and a Ph.D. in physical chemistry from Oregon State University. His research interests include the epitaxial growth of metal oxide crystalline films and multilayers, as well as the electronic, magnetic, and photochemical properties of oxide surfaces, and oxide/oxide, oxide/metal and oxide/semiconductor interfaces. He has authored or coauthors ~200 refereed research articles, invited review articles, and book chapters, holds three U.S. patents, and has given ~160 invited lectures at conferences, universities and research laboratories worldwide. He is a Fellow of the AVS, the Science and Technology Society, as was the 2004 recipient of the E.W. Mueller Award for outstanding achievements in surface science, conferred by the Laboratory for Surface Studies at the University of Wisconsin at Milwaukee.