Prof. Xiuling Li
Department of Electrical and Computer Engineering
University of Illinois, Urbana-Champaign
Monday, May 17, 2:00-3:00pm
Allen (CIS) 338X
This talk focuses on two types of III-V compound semiconductor nanotechnology building blocks and their potential applications in nanoelectronics, nanophotonics, and MEMS/NEMS: III-V semiconductor nanowires (NWs) and nanotubes (SNTs).
Interest in semiconductor NWs have increased exponentially over the past several years because of their unique optical and electrical properties and the capability of producing high quality heterostructures with large lattice mismatch on the nanometer scale. Integration of semiconductor nanowire based devices has been problematic and usually requires the technologically disadvantageous (111) substrate for vertical nanowire devices or ex-situ assembly techniques to align planar nanowire devices. In the first part of the talk, I will present our discovery of a type of NWs that are twin-defect free, high carrier mobility, self-aligned, and transfer-printable. The planar nanowire growth and doping mechanism by MOCVD, as well as the output and transfer characteristics of a long channel MESFET using such GaAs nanowire as the channel material will be analyzed.
SNT on the other hand is an emerging field that has only caught limited attention, yet possesses the potential to provide a wide range of functionalities. It is formed by a combination of top-down and bottom-up approach through the self-rolling of strained thin films. This allows feasible large area assembly and integration with existing semiconductor technology, while maintaining the control of the tube size and heterojunction formation in the tube wall. In the 2nd part of the talk, I will discuss the formation process, large area assembly, and optical characterization of InxGa1-xAs/GaAs micro and nanotubes with active light emitting media incorporated in the tube wall. Device prospects of SNTs for nanophotonics and MEMS will be explored.
Biography: Xiuling Li received her Ph.D. degree from the University of California at Los Angeles. She joined the faculty of the University of Illinois in 2007, after working at a startup company for six years. She is currently an assistant professor in the Department of Electrical and Computer Engineering, and an affiliate faculty member of the Department of Materials Science and Engineering and the Beckman Institute. Her current research interests are in the area of nanostructured semiconductor materials and devices. She has won the NSF CAREER award (2008) and DARPA Young Faculty Award (2009). Her group's work on the planar nanowires has won one of the best student paper awards at the 2008 IEEE LEOS annual meeting. The micro and nanotube work has been identified as an outstanding symposium paper presented at the 2008 MRS meeting.
Hosted by: Prof. H.-S. Philip Wong
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