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Peter Moeck, Department of Physics, www.physics.pdx.edu/~pmoeck Peter Moeck Dr. rer. nat. R.W. Chan: “one cannot easily get degrees in … crystallography”,

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Presentation on theme: "Peter Moeck, Department of Physics, www.physics.pdx.edu/~pmoeck Peter Moeck Dr. rer. nat. R.W. Chan: “one cannot easily get degrees in … crystallography”,"— Presentation transcript:

1 Peter Moeck, Department of Physics, Peter Moeck Dr. rer. nat. R.W. Chan: “one cannot easily get degrees in … crystallography”, The Coming of Materials Science, Pergamon, 2001 Somehow, I managed to get two of them ! Research Interests generally: application of physical crystallography to materials science and engineering problems of current and future semiconductor technologies recently: unintentional plastic deformation of GaAs wafers and ingots currently: self assembled epitaxial semiconductor quantum dots complementary: goniometry of direct and reciprocal lattice vectors in TEM (methodical and software development)

2 Peter Moeck, Department of Physics, recently: unintentional plastic deformation of GaAs wafers and ingots Funding: Engineering and Physical Science Research Council, U.K. X-ray topography at a synchrotron reveals dislocation structure Visible light interferometry measures surface steps Scanning infrared polariscopy quantifies shear strains all experiments combined → new model  technical modifications of equipment  unintentional plastic deformation gone for good P. Möck, J. Appl. Cryst. 34 (2001) 65; Cryst. Res. Technol. 35 (2000) 529, J. Cryst. Growth 224 (2001) 11

3 Peter Moeck, Department of Physics, currently: self assembled epitaxial semiconductor quantum dots Funding: Research Innovation Award, Campus Research Board of U of Illinois at Chicago AFM for individual shapes and sizes Triple crystal X-ray diffraction for shapes and sizes over cm -2 TEM and STEM revealed atomic ordering within the quantum dots for first time world wide! P. Möck et al. J. Appl. Phys. 79 (2001) 946  opportunity to create novel phases!! world wide patent pending unsolved problem: how to identify the crystallographic phases? Solution → complementary methodical developments, next slide P. Möck et al., IEE-Proc. Optoelectron. 147 (2000) 209 Photoluminescence spectroscopy to prove quantum dot activity

4 Peter Moeck, Department of Physics, complementary: goniometry of direct and reciprocal lattice vectors in TEM (methodical and software development) Basic Ideas: determine crystallographic orientation of crystal with respect to microscope coordinate system, i.e. determine a set of transformation matrices, make crystallographic analyses, e.g. phase identification, orientation relationships, grain boundary parameters, by manipulating these matrices, … works without recourse to recorded high resolution phase contrast images or diffraction patterns, can be done right at the microscope (but needs a good specimen stage and compucentricity) Plans: implement at software level at PSU’s FEI Tecnai G 2 F-20 TEM/STEM, employ for identification of crystallographic phase of non-cubic semiconductor quantum dots and other nanocrystals, (i.e. solve problem last slide), develop further in years to come for all kinds of crystallographic analyses Collaborators on this project: Prof. P. Fraundorf, U. of Missouri at St. Louis, Dr. W. Qin, Digital DNS Lab Meza, Motorola, W. Qin & P. Fraundorf, Ultramicroscopy 94 (2003) 245 German patents: DE A1 and DD A7, 11/21/1989, description and references at


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