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Kenta Kuroda honored with “Academic Lecture Encouragement Prize”

20. May 2017/in News /by sfb1083

Dr. Kuroda and Prof. Dr. Höfer in the lab at the University of Marburg (Photo: Univ. Marburg).

At the 36th academic lecture sponsored by the Japan Surface Science Association (SSSJ) held at the Nagoya International Conference Hall on November 29th in 2016, Kuroda gave an excellent general presentation on “Ultrafast dynamics of Dirac surface states in topological insulators” which is expected to make a significant contribution to the development of surface science.

Topological insulators are insulators in which only the outermost surface reveals a metallic state. As surface electrons are crucial in shaping the material functions, understanding details of the mechanics and processes at work has drawn worldwide attention. Kuroda and colleagues were the first to successfully apply short laser pulses and time-resolved photoelectron spectroscopy in the mid-infrared region in their investigations. As the researchers analyzed the photo excitation of Dirac surface-electrons generated in topological insulators at femtosecond resolution, they were able to show a direct optical transition of the Dirac surface condition in response to the mid-infrared excitation with a resulting spin-polarization of the surface current. The SSSJ sees this discovery as an important step to achieving optical spin control of electrons solely by the means of light.

The award is granted to promising young researchers under the age of 32 years and the presentation ceremony took place at the Surface Science Society of Japan’s regular meeting on May 20th, 2017.

The underlying research work was performed in close collaboration with colleagues in Japan and from SFB-project B6 (Höfer) during Dr. Kuroda’s research stay as a JSPS fellow and guest scientist of SFB 1083 at the Philipps-Universität Marburg in 2014 and 2015.

SFB 1083 Winter School at Schloss Rauischholzhausen

17. January 2017/in News /by sfb1083

Castle Rauischholzhausen in winter (Photo: Castle Rauischholzhausen).

SFB 1083’s biannual winter school for its young researchers

More than 50 young staff-members involved in the various physics- and chemistry-based SFB 1083 subprojects have come together in Schloss Rauischholzhausen near Marburg for two days of talks and intensive discussion of their research. Invited speakers from Germany and abroad round of the program by contributing more technical tutorials and presentations of their research.

Invited Speakers: Ellen Backus (Mainz), Alexey Chernikov (Regensburg), Matteo Gatti (Gif-sur-Yvette), Christian Papp (Erlangen-Nürnberg), Katrin Siefermann(Leipzig)

Link to abstract-volume and report.

Interface between Silicon Technology and Organic Chemistry – Publication by A8 (Koert/Dürr) and B5 (Höfer)

25. November 2016/in News /by sfb1083

Chemists and physicists of SFB projects A8 (Koert) and B5 (Höfer) demonstrate for the first time the controlled chemoselective attachment of bifunctional organic molecules to silicon.

Interface between semiconductor technology and organic chemistry: cyclooctyne selectively attaches to the Si-surface allowing additional functional groups to remain free (image: Marcel Reutzel & Michael Dürr; image may be used in reporting on the publication in JPCC only). Reprinted with permission from N. Reutzel et al, J. Phys. Chem. C 120, 46, 2016, 26284-26289. Copyright 2016 American Chemical Society.

With these results, which were highlighted on the cover page of The Journal of Physical Chemistry, an interface between silicon and organic multilayers has been created [1]. This interface opens the road for a controlled functionalization of silicon with organic molecules. In this way, it offers new perspectives in semiconductor technology (“More than Moore”).

Chemoselective attachment of multifunctional organic molecules is the first fundamental process step for the controlled organic functionalization of semiconductor surfaces. However, the high reactivity of pristine silicon surfaces, especially of the technologically most relevant Si(001) surface, has prohibited so far such a controlled functionalization: multifunctional molecules do not show chemical selectivity on these surfaces but are found with different functional groups attached.

In a joint effort, chemists and physicists of the SFB 1083 “Structure and Dynamics of Internal Interfaces” developed for the first time a general strategy for solving this problem: Using substituted cyclooctynes, they obtained well-defined inorganic-organic interfaces on Si(001) with the bifunctional molecules attached to the silicon surface solely via a cyclooctyne’s strained triple bond. The second functionality is thus available for further building up of complex molecular architectures, e.g., using organic click chemistry. The strategy for the observed chemoselectivity is based on the distinctly different adsorption dynamics of the separate functional groups and thus widely applicable.

In combination with the results for controlled multilayer synthesis in solution using the same classes of molecules [2], this work is a promising basis for a multitude of applications combining semiconductor technology and organic chemistry, e.g., the integration of optically active organic layers on silicon devices. The obtained structures are also of high interest for further studies of the electronic properties at organic/semiconductor interfaces within SFB 1083.

Publication:

[1] M. Reutzel, N. Münster, M. A. Lipponer, C. Länger, U. Höfer, U. Koert, M. Dürr, Chemoselective Reactivity of Bifunctional Cyclooctynes on Si(001),
J. Phys. Chem. C (2016), DOI: 10.1021/acs.jpcc.6b07501.

[2] N. Münster, P. Nikodemiak, and U. Koert, Chemoselective Layer-by-Layer Approach Utilizing Click Reactions with Ethynylcyclooctynes and Diazides,
Org. Lett. 18, 4296 (2016), DOI:10.1021/acs.orglett.6b02048.

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