TcSUH EventS
Seminar
Scientific and Technological Opportunities of Ultra-High Density Nanowire Arrays
by: Dr. Dunwei Wang
Date: Wednesday February 14, 2007
Time: 11:00 am – 12:00 pm
Location: Science & Research Building 1 – Building 550 — Room 634
Overview
With their dimensions exceeding conventional lithographic methods limit, semiconductor nanowires have attracted intensive research efforts as building blocks for future electronics. While various individual nanowire-based devices are demonstrated to outperform existing MOSEFT, successful integration into complex functional units is still missing. The fundamental distinction between current semiconductor technology and nanowire-based electronics is that the latter requires regular device structures for optimum performance, whereas the former relies on fabricating arbitrary ones based on functionalities. This imposes great challenge of nanowire research in terms of arrangement and integrations. I will present our recent advancements in this area using ultra-high density nanowire arrays with excellent arrangement for electronic applications. A wide range of topics will be covered and they include controlled placement of p- and n-type nanowires in a single array; understandings of the surface effects on nanowire electrical properties; statistically significant high performance field effect transistors and monolithic Si-only nanowire networks. Integrated nanowire circuitries with complementary symmetry are therefore enabled for energy efficient applications and they are amenable to high degree of integrations. Furthermore, our studies shed light on nanoscale sciences and technologies in general and will pave ways toward many applications in relevant scales such biological sensing and energy conversions.
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Special Seminar
How the bc1 Complex Works: Killing you Softly with a Dance
by: Antony R. Crofts
Date: Monday February 12, 2007
Time: 12:00 pm – 1:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
Redox enzymes of the bc1 complex family form the central components of all the major energy conversion processes that fuel the biosphere. Oxidation of a membrane-bound quinol (QH2, - ubihydroquinone in mitochondria and a-proteobacteria) by a higher potential acceptor (cyt c or c2) is linked to transport of protons across the membrane through a modified Q-cycle. The reaction in which QH2 is oxidized suffers from a defect. Evolution designed the mechanism before the atmosphere became aerobic, and the intermediate semiquinone (SQ) has a potential suitable for rapid reduction of O2 to superoxide (SO). As a consequence, the catalytic site (the Qo-site) is a potential source of SO, which is a precursor of a variety of reactive oxygen species (ROS) that cause damage to DNA and proteins. A substantial literature suggests that the bc1 complex is the main culprit in ROS-generated damage under a variety of pathological conditions. Under conditions in which the intermediate SQ might be expected to accumulate, a significant rate of SO production can be measured. However, under normal operation, the isolated complex does not generate detectable amounts of SO. I will review the modified Q-cycle, and discuss the mechanism of the Qo-site of the bc1 complex, with an emphasis on the molecular ballet at the site through which SO production and other bypass reactions are minimized.
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Conferences and Workshops
4th U.S. Air Force-Taiwan Nanoscience Initiative Workshop
by: TcSUH Administration
Date: Thursday February 08, 2007
Time: 7:30 am – 9:30 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
The Air Force Office of Scientific Research (AFOSR) of the U.S. Air Force Research Laboratory (AFRL) and National Science Council (NSC) in Taiwan and are pleased to announce that the 4th U.S. Air Force/Taiwan Nanoscience and Nanotechnology workshop will be held on February 8-9, 2007 at the main campus of the University of Houston (UH). All oral and poster presentations will be held in the UH Athletics/Alumni Center, located at 3100 Cullen Boulevard, Houston, TX 77004. We invite you to join us at the workshop.
The first and second Taiwan/U.S. Air Force workshops were held in Maui and Honolulu, Hawaii, and the third was held in Hualien, Taiwan. This series of U.S. Air Force/Taiwan Nanoscience Initiative Workshops aims to provide a stimulating and thought-provoking forum for sharing the latest technical developments and ideas in nanoscience and nanotechnology.
Please visit the U.S. AF-Taiwan Nanoscience Initiative Workshop website for more information.
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Conferences and Workshops
SPRING Conference IV - 2007
by: TcSUH Administration
Date: Tuesday February 06, 2007
Time: 12:00 am – 12:00 am
Location: Houston Science Center – Building 593 — Room 102
Overview
Please visit the SPRING web site for more information.
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Special Seminar
III-Nitrides Materials Grown by Plasma-Assisted Molecular Beam Epitaxy
by: Prof. Li-Wei Tu
Date: Monday February 05, 2007
Time: 1:00 pm – 1:45 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
GaN, InN, AlN, and their alloys have tremendous usages in many different areas of electronics and optoelectronics. Light-emitting diodes for lighting, decoration, displays, traffic signals, and laser diodes for pointers, DVD players and recorders, sensors in detectors, solar cells for energy conversion, field-emission transistors in power devices, etc. are but some examples. In this talk, I would like to discuss some contemporary issues faced by the community and then present some interesting topics in which our laboratory has engaged. After an introductive overview of the III-nitride family, I will discuss an unusual controversy on the fundamental band gap of InN. The debates, which started in 2002 and continued unabated even up to this day, are mainly on whether the material’s energy band gap is ~1.9 eV or ~0.7 eV. I will present the current status also on the non-polar nitrides’ growth and their advantages over the traditional polar ones, which is a relevant issue challenging the viability of the III-nitride technology. I will conclude with the nanostructures of III-nitrides and their potential applications in modern technology, which include the use of some basic forms such as nanorods and nanotips.
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