Materials Science Seminar

Fabrication and Characterization of
Nanoscale Hybrid Structures and DevicesJia Grace Lu
Department of Chemical Engineering and Materials Science
Department of Electrical Engineering and Computer Science
University of California, IrvineIn this talk, I will describe the research on the nano materials and hybrid structures currently undertaking in my group. By integrating bottom-up synthesis technique with top-down lithographic technique, various nanostructures are fabricated, and they are characterized by different methods such as TEM, SEM, XRD, photoluminescence, photoconductance, scanning surface potential microscopy, and electrical transport measurement. These nanostructures are used to build a range of electronic devices including field effect transistors (FET), chemical sensors, and single-electron transistors (SET). For example, individual ZnO nanowire FETs are implemented as highly sensitive chemical sensors for detection of NO2, NH3, CO toxic gases. Due to a Debye screening length comparable to the nanowire diameter, the electric field applied over the back gate electrode can significantly affect the sensitivity. A strong negative gate field is also found to efficiently refresh the sensors via an electrodesorption mechanism. As another example, spin dependent transport is studied in ferromagnetic SET devices with Co/Al2O3/Al nanoscale tunnel junctions. They exhibit typical single electron tunneling behavior including Coulomb blockade and gate modulation. Magnetoconductance measurements show bell-shaped I - H curves as a result of the direct influence of the magnetic field on the superconducting gap. In addition, the magnetic moment switching in the Co electrodes from parallel to antiparallel configurations give rises to a rich phenomenon of spin transport. Different transport mechanisms based on the spin accumulation effect and the Meservey-Tedrow effect will be presented. Brief Bio-Sketch:Dr. Lu received her dual B.S. degrees in Physics and Electrical Engineering from Washington University in 1992, M.S. and Ph.D. degrees in Applied Physics from Harvard University in 1993 and 1997, respectively. Currently she holds a joint appointment in the Department of Electrical Engineering and Computer Science and the Department of Chemical Engineering and Materials Science at UC Irvine. She had received the National Science Foundation Career Award in 2002 and the Presidential Early Career Award for Scientists and Engineers in 2004.

Location: Seaver Science Library (SSL) - 150

Audiences: Everyone Is Invited

Contact: Petra Pearce