Date 2015-09-01 
The Fall Semester Seminar

■ Topic : Kinetics of nano-structure formation using in-situ TEM
■ Speaker : Prof. Bong-Joong Kim (School of MSE, GIST)

■ Date & Time  :  September 1 (Tue), 16:00
■ Venue : KAIST Applied Engineering B/D(W1), Multimedia Lecture Hall (1st Floor)
■ Abstract : When considering nanowires as candidates for the active elements in electronic and optoelectronic devices, a high level of control over their nucleation and growth is necessary. In particular, before nanowires can become part of a manufacturing process, their initial growth stages including nucleation must be sufficiently well understood that they can be grown reliably at each desired site with well-controlled diameter, length, and orientation. Besides nanowires, thermal growth techniques also produce other splendid and abundant configurations of nanostructures of compound semiconductors including negative nanowires, nanoribbons and nanosheets that have potential uses in electronic and optoelectronic device applications.
   In this talk, a broad range of topics that are largely centered on mechanisms and kinetics of nanowire nucleation and growth in group IV –Si and Ge, group III-V – GaN and group II-VI – ZnO to develop the essential understanding of the nanowire growth regimes such as vapor-liquid-solid(VLS) and vapor-solid-solid(VSS), the related phase transformations, the changes in phase diagrams, and the size effects of catalysts by combining in situ quantitative measurements and theoretical modeling. These studies exploited the high spatial resolution and time resolved nature of in situ transmission electron microscopes (TEM) equipped with chemical vapor deposition facilities to directly observe the phase evolution and growth processes while introducing source gases (i.e. Si2H6 and Ge2H6) and evaporating substrates (i.e. GaN and ZnO) in the microscopes. Recent advanced topics and other in situ TEM approaches of forming nanostructures such as liquid cell study are also briefly introduced.