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R. Krupke
Research Unit Chair
Charge transport and light-matter interaction in carbon nanosystems
ralph krupkeBgl6∂kit edu

KIT Campus North
Building 640


Charge transport and light-matter interaction in carbon nanosystems

Molecular nanostructures such as carbon nanotubes and graphene have fascinating properties and are of great interest to science and technology. We integrate the material into complex device structures, perform fundamental science experiments, and explore the materials potential for electronics, optoelectronics and sensing applications.

Our current research focus is on:

  • Nanoscale light emission and detection
  • Graphene-based device structures
  • Carbon Nanotube based Solar Cells



Our research is funded by the Helmholtz Program Science and Technology of Nanosystems (STN) and we are part of the subtopic Carbon Nanosystems. Major external funding is provided by the VolkswagenStiftung and the German Science Foundation.
*The research unit hosts the Emmy-Noether-Group of Dr. B. Flavel working on carbon nanotubes based solar cells and sensors.


Here are some milestones that we have reached over the last decade:

  • Separation of metallic from semiconducting carbon nanotubes
  • Parallel assembling of carbon nanotube into high-density devices arrays
  • Light emission from single nanotube-molecule-nanotube junctions
  • Narrow-band thermal light emission from cavity-controlled graphene transistor
  • 153GHz semiconducting carbon nanotube transistor
  • Waveguide-integrated carbon nanotube emitters

If you have questions regarding our research and job opportunities don't hesitate to send us an email!



DC Josephson effect in a graphene-based QPC

The effect of a quantum point contact confinement and an external magnetic field on the supercurrent has been demonstrated in a bilayer graphene heterostructure.

Nat. Commun. 9, 1722 (2018)
First Quantum Photonic Circuit with an Electrically Driven Light Source

Optical waveguide integrated generation and detection of non-classical light with electrically driven carbon nanotubes.

Nature Photonics 10, 727–732 (2016)
Towards on-chip communication with carbon nanotubes
Towards on-chip communication with carbon nanotubes

Electrically driven nanotubes can be forced to emit light with a specific color by integration into photonic crystal waveguide.

Nature Photonics 10.1038/nphoton.2016.70
short-channel CN transistor
Carbon nanotubes for high-density short-channel transistors

Best performing short-channel transistors have been built by using highly enriched semiconducting single-wall CNs prepared by combining polymer-wrapping with size-exclusion chromatography.

ACS Nano 10, 1888 (2016)
NT15 in Nagoya/Japan

Congratulations to Daniel Tune / Ben Flavel and Ralph Krupke / Feliks Pyatkov who won two poster awards in NT 2015


[NT15 in Nagoya/Japan]

Congradulations to Felix Pyatkov who won a best poster award in WONTON 2015


[WONTON 2015]
Gel Permeation Purifies DWCNTs

Our work on the electronic separation of DWCNTs was covered by Nanotechweb.  Thanks again to Belle Dume for all of the great publicity.  

Full Article Here
Electronically Sorted DWCNTs

Building on our previous work we show that chromatography techniques can be used to prepare DWCNTs with either metallic or semiconducting outer walls.

ACS Nano, March 2015, DOI: 10.1021/nn506869h
Ms. Moore now Dr. Moore

Congratulations to Dr. Moore who successfully completed her PhD in February 2015 and for being awarded the Flinders University's Best Paper Award for her work on DWCNTs

Pat Goldberg Memorial Award
INT researchers awarded IBM Best Paper Award

"Light-matter Interaction in a Microcavity-controlled Graphene Transistor," co-authored by  Dr. Michael Engel, Prof. Hilbert v. Löhneysen and Prof. Ralph Krupke and researchers from Cambridge University and IBM, is one of five papers to win this year's Pat Goldberg Memorial Award for the best papers published in 2012.

KIT press release
Shedding Light on CNT Photocurrent

Following on from our recent publication on photocurrent spectroscopy from SWCNTs we were once again privileged to have our work covered by the UK based nanotechnology website Nanotechweb.

Full Article Here
We demonstrate how light from an electrically driven carbon nanotube can be coupled directly into a photonic waveguide architecture

Waferscale, broadband sources are realized integrated with nanophotonic circuits allowing for propagation of light over centimeter distances.

[Advanced Materials]
Automated Preparation of (n,m) Pure SWCNTs With the use of a Gel Permeation Chromatography system we demonstrate the simple, scalable and automated separation of (n,m) pure s-SWCNTs. ACS Nano 8 (2014) 1817-1826
Gold-coated AFM tip
Nanotechnology Cover

"Enhancing Raman signals with an interferometrically controlled AFM tip" got on the cover of Nanotechnology magazine.

[ Nanotechnology ]
Molybdenite emitting light
Physics World article on electroluminescence of Molybdenite

Physics World covered our research on electroluminescence of MoS2 layers

[ Physics World ]
Advanced Energy Materials Cover

 "Carbon Nanotube-Silicon Solar Cells" got on the cover of Advanced Energy Materials.

[ Advanced Energy Materials ]
Nanoparticle etching a tunnel into graphite
F.A.Z. article on world's smallest tunnels The Frankfurter Allgemeine Zeitung covered our research on nanoparticles etching tunnels into graphite.
[ F.A.Z. ]

Further Press Coverage