Abstract
The metalorganic vapor phase epitaxy of semiconductor materials has been developed over the past three decades and has focused on the formation of semiconductors and alloys useful in the formation of optoelectronic and high speed electronic devices. These materials are generally binary semiconductors or alloys which have broad miscibility. The extension to alloy systems which are highly immiscible in bulk form requires modification to conventional growth systems preventing the nucleation and growth of multiple compositional phases. The formation of these multi-component alloys is discussed in terms of their known thermodynamic behavior which can be altered by the presence of strain in the material and the growth temperature. Additionally, the stoichiometry and reaction kinetics of the alloy constituents can impose kinetic constraints allowing for the formation of alloys within the miscibility gap. This talk will review and discuss those influences in determining the film composition and microstructure of the model alloys GaAsSb and GaAsN which have both thermodynamic and chemical influences on the formation of the alloy. The extension of this work to more complex alloys, such as 5 element or quinternaries, which open the palette of device materials, will be discussed.
About the speaker
Thomas Kuech received his PhD from Caltech in 1981. He was a Research Staff Member at the IBM T.J. Watson Research Center from 1981 to 1990. Since 1990, he has been a member of the faculty of the Chemical and Biological Engineering Department at the University of Wisconsin – Madison, where he is currently the Milton J. and A. Maude Shoemaker Professor.
Prof Kuech is a Member of the US National Academy of Engineering and has been honored as a Fellow of the American Physical Society, several named lectureships, the American Institute of Chemical Engineering Stine Award, and is a concurrent professor of Nanjing University in the Department of Physics. While at UW-Madison, he was the inaugural director of the UW-Madison Materials Research Science and Engineering Center. He has also served as an executive officer in several professional societies, such as president of the American Association for Crystal Growth, as well as organizing and chairing several major national and international conferences.
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Free and open to the public. Seating is on a first-come first-served basis.
Institute for Advanced Study
Enquiries ias@ust.hk / 2358 5912
http://ias.ust.hk
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