Thermal stability and diffusion phenomena in metal/semiconductor superlattice thin films observed by aberrationcorredted TEM-methods at atomic resolution

29.04.2019 von 16:00 bis 17:00

Australian Centre for Microscopy & Microanalysis, The University of Sydney, NSW 2006, Australia.

Sophisticated aberration-corrected high-resolution transmission electron microscopy (HRTEM) imaging and spectroscopy methods are nowadays commonly applied for inves-tigations of materials systems at the atomic level. A brief recapitulation on the development of such instruments and the methods that became available with them will be given in the first part of the presentation.

Secondly, the application of several HRTEM imaging and spectroscopy techniques for the study of thin films will be demonstrated. Epitaxial metal/semiconductor nitride superlattices and multilayers are known to be promising candidates for applications as ultra-hard- and thermal- coatings, as well as for thermoelectric and plasmonic devices [1]. It was recently demonstrated that such superlattices can be grown epitaxially with low-defect densities by magnetron sputtering on [001] MgO substrates [2-4].

I will give an overview on the growth and microstructure of such systems, and present TEM-based results on the thermal stability [5-7] and plasmonic properties [8] of various metal/semiconductor nitride combinations. Fundamental insights into diffusion processes were gained directly from atomic level STEM and EDS (energy-dispersive X-ray spectros-copy) images. Moreover, the onset and progression of dislocation-pipe diffusion under se-quential annealing could be studied at direct atomic resolution for the first time [9].


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[8] B. Saha, Y. Rui Koh, J. Comparan, S. Sadasivam, J. L. Schroeder, M. Garbrecht, A. Mohammed, J. Birch, T. Fisher, A. Shakouri, and T. D. Sands, Phys. Rev. B., 93, 045311 (2016).
[9] M. Garbrecht, L. Hultman, M. H. Fawey, T. D. Sands, and B. Saha, J. Mater Sci. 53(6) 4001-4009, (2018).
[9] M. Garbrecht, B. Saha, J. L. Schroeder, L. Hultman, and T. D. Sands, Sci. Rep. 7, 46092 (2017).

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