Chair of Nanoelectronics

Prof. Dr. Hermann Kohlstedt

Kaiserstraße 2, R.C 004
Phone: +49 431 880-6075
Telefax: +49 431 880-6077
hko@tf.uni-kiel.de

Information about Prof. Dr. Hermann Kohlstedt

Research interests

My research interest covers the field of novel electronics devices from device fabrication, thin film analytics to electrical characterization. Examples include the non-linear dynamics of interlayer fluxon (soliton) interactions in stacked superconducting tunnel junctions and the memristive electronic transport in multiferroic tunnel junctions. His main research aims are memristive devices for non-volatile memories and neuromorphic circuits. Especially the experimental realization of time-varying, pulsed-coupled bio-inspired neuronal oscillator networks, comprising signal delay and variable coupling strengths (via memristive devices) attracted his research interest over the last years. 

  • Memristive devices and circuits for bio-inspired electronics
  • Current transport in superconducting, ferroelectric and multiferroic tunnel junctions
  • Interface and surface spectroscopy using photons and electrons
  • Non-linear dynamics in multilayered long Josephson junctions
  • Thin film technology and device patterning

 

Professional Development and Research Interests

Hermann Kohlstedt is Professor of Nanoelectronics at the Engineering Department of the Christian-Albrechts University (CAU) Kiel, Germany. Prior to this appointment at CAU, he was leading a research group from 1991 to 2009 at the Research Center Jülich, Germany that focused on advanced electronic device concepts and associated materials-processing issues. From 1986 to 1989 he worked at the Institute for Millimeterwave Radiostronomy (IRAM) in Grenoble, France and received his PhD in Physics from the Kassel University in 1989 on superconducting tunnel junctions for heterodyne receivers. From 1990 to 1991 he held a one year appointment at the Advantest Corporation in Sapporo, Japan.  In 2000 he received his habilitation in Experimental Physics at the Department of Mathematics and     Natural Sciences of Cologne University, Germany.

In 2005/06 Hermann Kohlstedt was on sabbatical at the Materials Science Department of the UC Berkeley and the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory, USA with research focus on in-operando soft-Xray spectroscopy of ferroelectric devices. Since 2009 he is working in the field of memristive device for neuromorphic circuits and he is spokes man of the DFG (German Research Society) Research Group FOR2093 entitled: “Memristive Devices for neuronal Systems”. He authored and co-authored more than 170 papers in peer-review journals. 

2009 – today: Head of the Chair Nanoelectronics, Institute for Electrical Engineering and Information technology, Technical Faculty, CAU Kiel.

2000 – 2009: Institute for Solid State Research, Research Center Jülich, Development  of ferroelectric capacitors ferroelectric field effect transistors and ferroelectric tunnel junctions (FTJs) for non-volatile memory applications, scaling effects in ultrathin epitaxial ferroelectric layers (BaTiO3 und PbZrxTi1-xO3). 

2005 – 2006: annual sabbatical at the UC Berkeley (Material Science Department) and Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA, in-situ analytics of ferroelectric capacitors by soft X-ray absorption spectroscopy (SXAS), Installation of a pulsed Laser deposition system (PLD) at an ARPES beam line.

2000 Habilitation at the University of Cologne, Department of Mathematics and Natural Sciences, 2nd Institute of Physics.

1991 – 1999: Institute of Thin Film and Ion Technology (ISI), Research Center Jülich, Germany: First experimental evidences of solitons (flux quanta) in multilayered, superconducting long Josephson tunnel junctions, Research on HTC step-edge junctions for field effect transistor applications, HTc Josphson mixer and hot electron bolometer for heterodyne receivers. Research on magnetic (CoFe/Al2O3/CoFe) tunnel junctions for non-volatile memories.

1990 – 1991:  Advantest Laboratories, Sapporo, Japan and University Hokkaido (Depart. of Electr. Eng.) Reearch on HTc superconductors and telegraph noise in tunnel junctions.

1986 – 1989:  PhD thesis at the Insitut de Radioastronomie Millimétrique (IRAM, Max- Planck - CNRS), Grenoble, France: Development of superconducting (SIS) quantum mixer (Nb-AlOx-NbAl/AlOx/Nb junctions) for frequencies up to  230 GHz. Application of such junction in a radio astronomy  sub-mm-wave telescopes. Post-Doc position in IRAM until March1990.

1980 – 1986: Study of Physics at the TH-Darmstadt and the University of     Kassel (Diploma in Physics 1986), Development of an electron beam writing system on the basis of a scan electron microscope.