Brown University
Joint Materials/Solid Mechanics Seminar Series
Chairman, Department of Mechanical and Aerospace Engineering, Princeton University | |
Abstract: While the equilibrium morphology of an equilibrium single crystal can be understood in terms of the anisotropic grain boundary energy, practical crystal growth methods invariably operate far from equilibrium. In this talk, I will examine some of the basic concepts of crystal growth morphology and focus on one special, yet common, case. That is, where the growth rate is anisotropic and only depends on the crystallographic orientation of the crystal surface. I will first examine the conditions under which this anisotropy controls the morphology. Chemical vapor deposition of covalent materials often operates under such conditions. I will show some experimental examples taken from the Epitaxial Lateral Overgrowth (ELO) of GaN. Next, I will show how to deduce the key features of the growth rate anisotropy from experimental observations. Finally, I will employ a level set simulation method to show that the deduced anisotropy (and the simulation method) are capable of describing nearly all of the essential features of GaN growth. I will conclude with a discussion of how to use these new results to "design" crystal growth morphology.
Special Colloquium
Rescheduled for Tuesday, December 13, 2005
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