Quantum Materials and Devices for Advanced Technologies

Low-dimensional materials and molecular nanostructures such as graphene and carbon nanotubes have fascinating properties and are of great interest to science and technology. We integrate these quantum materials into complex device structures, carry out state-of-the-art experiments and explore the potential for electronic, optoelectronic, photonic, and sensory applications. We are currently working on:

  • Nanoscale light-emitting devices and detectors for integrated optoelectronics
  • Single-photon emission from quantum defects for quantum information processing
  • Interfacing quantum materials devices with metal-organic frameworks for ultra low-power gas sensing
  • Assembling nanocarbon ordered layers and thin films for solar cells and optical applications
  • Fabricating 2D van der Waal heterostructures, 1D hybrid materials, and scale-bridging devices (3D->0D)
  • Tailoring charge-transport in low-dimensional materials devices for next-generation nanoelectronics


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!


On the mechanism of piezoresistance in nanocrystalline graphiteSandeep Kumar
On the mechanism of piezoresistance in nanocrystalline graphite

Piezoresistivity in thin films of nanocrystalline graphite is explored by utilising sheet resistance and Raman spectroscopy.

Beilstein J. Nanotechnol. 2024
Correlation Measurements for Carbon Nanotubes with Quantum DefectsMin-Ken Li
Correlation Measurements for Carbon Nanotubes with Quantum Defects

Photon antibunching from electrically-biased quantum defects in graphene-contacted single-walled carbon nanotubes at 77K. 

ACS Nano 2024
office outing, 2024.01
Group excursion, January 2024

Group outing to the Teufelsmühle, in the snowy Northern Black Forest.

Enhanced Broadband Photodetection with Geometry and Interface Engineered Nanocrystalline GraphiteDevang Parmar
Enhanced Broadband Photodetection with Geometry and Interface Engineered Nanocrystalline Graphite

Nanocrystalline graphite in a suspended constriction configuration improves photodetection in the NIR-SWIR spectrum with enhanced photoresponse and detectivity.

Advanced Sensor Research 2023
Sensitive Detection of a Gaseous Analyte with Low-Power Metal–Organic Framework Functionalized Carbon Nanotube TransistorsSandeep Kumar
Sensitive Detection of a Gaseous Analyte with Low-Power Metal–Organic Framework Functionalized Carbon Nanotube Transistors

Detection of gas molecules at ppb concentrations is achieved using low power metal organic framework functionalised carbon nanotube transistors.

Advanced Electronic Materials 2023
Farewell party_Anirudh
Farewell to Dr. Peyyety

Congratulations to Dr. Naga Anirudh Peyyety who successfully completed his PhD in 2022. All the best for your future!

Electroluminescence from Single-Walled Carbon Nanotubes with Quantum DefectsMin-Ken Li
Electroluminescence from Single-Walled Carbon Nanotubes with Quantum Defects

Electroluminescence spectroscopy from single-tube devices based on (7,5) carbon nanotubes, functionalized with dichlorobenzene molecules have been demonstrated.

ACS Nano 2022
Tailoring Spectrally Flat Infrared Photodetection with Thickness-Controlled Nanocrystalline GraphiteKrupke
Tailoring Spectrally Flat Infrared Photodetection with Thickness-Controlled Nanocrystalline Graphite

Photodetectors from nanocrystalline graphite (NCG) that are spectrally flat in the near-infrared to short-wavelength infrared region by tailoring the layer thicknesses were fabricated. 

ACS Appl. Mater. Interfaces 2022
group excursion
Group excursion, September 2021

Group outing on a sunny day in Karlsruher Grat, Ottenhöfen in the Black Forest.

@ Sandeep KumarSandeep Kumar
Sensing Molecules with Metal–Organic Framework Functionalized Graphene Transistors

A novel concept of sensing molecules is introduced, which combines the sensitivity of a graphene field-effect transistor with the selectivity of a metal–organic framework. 

KIT pressTU Darmstadt News

Advanced Materials 2021
Low-Temperature Electroluminescence of Excitons and Trions in Monochiral Carbon Nanotube Devices

Low-temperature Electroluminescence spectroscopy of ultra-short-channel devices made from (9,8) carbon nanotubes emitting in the telecom band were repoted with line widths down to 2 meV at 4 K.

ACS Nano 2020
Graphene & Co Annual Meeting 2019

110 participants from 15 countries enjoyed an inspiring meeting in Bad Herrenalb / Black Forest.

[Graphene & Co - Annual Meeting 2019]

Congratulation to Sandeep Kumar who won the best poster award in NT 2019

[NT19 Würzburg/Germany]

Congradulations to Felix Pyatkov who won a best poster award in NT 2018


[NT18 in Beijing/China]
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 nanotubesKrupke
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, 420–427 (2016)
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 26, 3465 (2014)
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 graphiteKrupke
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