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Research Overview

Our Interests

Growth and properties of catalytic, magnetic, dielectric, superconducting, and optical thin films; fabrication and characterization of thin film devices; properties of magnetic and superconducting ceramics; development and use of high throughput synthesis/evaluation experimental strategies

Our Group

photo of van Dover group, May 2009

  (Left to right)

Sophie Cahen, John Gregoire, Bruce van Dover, Jon Petrie, Anna Legard, Hanjong Paik, Taro Naoi, Paul Kim, Leo Small

photo taken: May, 2009

 

Our Project Descriptions

Prof. van Dover’s research is currently focused on exploring the properties of dielectric, optical, magnetic, and intermetallic thin films. In many cases we exploit high-throughput techniques to facilitate the understanding of novel materials. We also use high-throughput techniques—specifically thin film composition spreads—to discover new materials, exploring chemical systems that have not been thoroughly mapped by conventional one-off experiments, and for which there is neither empirical nor theoretical guidance regarding structure/composition/property relations.

For example, we use thin film deposition to explore complex amorphous dielectrics. Single-cation amorphous dielectrics such as SiO2 and Ta2O5 are widely used and have been extensively investigated for many years, but amorphous multi-cation oxides have only begun to be investigated recently. We use thin film composition spreads to identify and understand basic structure/composition/property relations in two- and three- cation systems, as well as to develop improved materials for scientific and technological applications. In one project we are seeking to achieve a high charge density, as needed for DRAM capacitors or for gating charge into semiconductors. One material discovered while Prof. van Dover was at Bell Labs, an amorphous Zr0.2Sn0.2Ti0.6O2 composition, can support a charge density eight times higher than SiO2. We are now using composition spreads to try to understand the mechanism behind this world-record performance.

Composition spreads are also central to our work in the Cornell Fuel Cell Institute. Intermetallic compounds have been shown to provide unique advantages for use in mobile fuel cells (e.g., for powering laptops or automobiles). We are conducting a broad search for multielement materials that can yield improved catalytic activity, decreased poisoning by impurities in the fuel, and/or lower cost. This project is conducted in close collaboration with the Directors of the Cornell Fuel Cell Institute, Profs. Abruña and DiSalvo.

Our composition spreads are synthesized using cosputtering from spatially separated (usually elemental metal) magnetron sputter sources, a technique pioneered by Prof. van Dover in the early 1980’s. For this purpose we have three custom-built sputtering chambers: a system designed for metal deposition of up to three elements at a time, a system designed for metal and ceramic (carbide, nitride, and oxide) deposition with four confocal sources, and a system designed for oxide deposition using 90º off-axis sputtering.

We also have extensive measurement capabilities, including electrical measurements of materials ranging from superconductors to insulators at frequencies from DC to 6 GHz and magnetic measurements (SQUID magnetometer and vibrating-sample magnetometer). These measurements can be executed from cryogenic temperatures (as low as 0.3 K) to 1000 ºC. We also do basic optical measurements and electrochemical measurements of catalyst activity. Many other characterization techniques are accomplished using the extensive facilities and infrastructure available at Cornell through the major scientific centers.

Our Home

Duffield Hall [Cornell NanoFabrication Facility]
Bard Hall [Materials Science & Engineering]
Duffield Hall : Honey, I shrunk my research ! Bard Hall : Making the music of the future !
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