Start Date

16-4-2019 4:00 PM

End Date

16-4-2019 5:00 PM

Abstract

The theory of elasticity accurately describes the deformations of macroscopic bodies under the action of applied stress. In this lecture I will examine the internal mechanisms of elasticity for strained-layer semiconductor heterostructures. In particular, I will present extended x-ray absorption fine structure (EXAFS) and x-ray diffraction (XRD) measurements to show how bond lengths and bond angles change with strain and compare with various theoretical models. These synchrotron-based experimental techniques and their application to thin films will be developed in detail.

Biography

Joseph Woicik earned a B.S. in Applied and Engineering Physics from Cornell University in 1983 and a M.S. and Ph.D. in Applied Physics from Stanford University in 1989. Currently he is a senior physicist at the National Institute of Standards and Technology where he works at the National Synchrotron Light Source-II, Brookhaven National Laboratory. He has published nearly 300 works on the application of synchrotron radiation to problems in physics and materials science, and in 2010 was awarded a cabinet award for his study of valence-electron emission in an x-ray standing-wave field.

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Apr 16th, 4:00 PM Apr 16th, 5:00 PM

Local Structural Determination in Strained-Layer Semiconductors

The theory of elasticity accurately describes the deformations of macroscopic bodies under the action of applied stress. In this lecture I will examine the internal mechanisms of elasticity for strained-layer semiconductor heterostructures. In particular, I will present extended x-ray absorption fine structure (EXAFS) and x-ray diffraction (XRD) measurements to show how bond lengths and bond angles change with strain and compare with various theoretical models. These synchrotron-based experimental techniques and their application to thin films will be developed in detail.