10.00 – 11.00, Reimaging Silicon
Dr. Michael A. Filler, School of Chemical & Biomolecular Engineering, Georgia Institute of Technology
Silicon is ubiquitous in modern semiconductor manufacturing. Well-established procedures for epitaxy, doping, etching, passivation, and contacting, perfected over more than five decades of use, enable a diverse array of electronic and photonic devices. Yet, the properties of bulk diamond cubic Si are fixed and ultimately limit its long-term usefulness. This talk will provide an overview of my group’s recent efforts to reimagine the structure and properties of Si at the nanoscale. We accomplish this task via nanowire engineering in general, and more specifically, by exploiting the unique synthetic capabilities of the vapor-liquid-solid (VLS) growth technique. Our experimental approach couples the real-time in-situ infrared spectroscopic interrogation of nanowire chemistry with post-growth structure and property characterization. By identifying the specific chemical bonds present during synthesis, we provide a robust foundation from which to rationally achieve novel materials. The role of surface chemistry as the root cause of well known, yet previously unexplained, semiconductor nanowire growth phenomena will be discussed in detail. We subsequently leverage this fundamental knowledge to control the bilayer stacking of Si atoms and enable thermodynamically metastable superstructures with user-programmable periodicity. The ability to incorporate impurity atoms at concentrations well beyond their bulk solubility limit also permits the generation and tuning of mid-infrared localized surface plasmon resonances, which greatly enhances the ability of Si to interact with electromagnetic radiation.
11.30 – 12.30, Use of ElectrodialysisElectrodeionization for Selective Separation in Biofuel Production
Dr. Jamie Hestekin, University of Arkansas
Liquid biofuels hold tremendous potential in helping to alleviate demand on fossil based fuels as well as improving the environment with lower carbon emissions. However, even with all the potential, they remain a sliver in the marketplace due the technical end economic challenges of their production. In many cases low level organic acids either need to be concentrated as a product intermediate or removed as an inhibitor. Electrodeionization is a technology that could hold the key for this separation problem. We are working on ways to do electrodeionization selectively so that productivity and selectivity in biofuels production can be greatly enhanced. This is an extreme challenge because many of the fermentation medias are quite complex which requires high levels of selectivity. This talk will outline some of the challenges that exist in biofuels production and show the approaches we are taking to address these challenges.