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MBE growth and doping of p-type oxides



Overview of the research project:

The p-type oxide NiO is an important charge barrier material for organic solar cells. This project investigates the growth of the p-type oxides NiO and SnO for basic investigations and combination with n-type oxides for all-oxide hetero p-n-devices. Systematic doping with nitrogen of these oxides and n-type oxides is investigated with the aim to influence the charge carrier concentrations. At a later stage, we develop the growth growth of another oxide, e.g. Cr2O3 or BaSnO3. The project comprises the following tasks:

Task 1. Further develop the MBE growth of NiO with high material quality and well defined surface based on preliminary growth results from a Master thesis. Possibly use MgO buffer layers to improve NiO material quality.

Task 2. Develop the MBE growth of SnO by gaining control over the parasitic Sn and SnO2 formation. The use of metal and suboxide sources is investigated and in-situ quadrupole mass spectrometry and laser reflectometry is used to measure the desorbing species and growth rate.

Task 3. Establish nitrogen doping for the above and n-type oxides by mixing N2 into the O2 plasma or by separate N2 plasma source. Investigation of the effect on transport properties.

Task 4. Grow p-n oxide heterostructures for p-n devices and to investigate charge transfer between the oxides, e.g. the gas-sensor relevant NiO on SnO2.

Task 5. (Optional) growth of another p-type oxide (e.g. Cr2O3), or the perovskite oxide BaSnO3 using a suboxide source.

Major accomplishments expected:

  • Provide high quality NiO for basic research
  • Reproducible growth of SnO and understanding of growth kinetics
  • Understand structural and electronic effect of defined N-doping
  • (optional) growth of a further oxide


Collaboration with partners in the project:

  • Structure, doping, point defects: Manfred Ramsteiner, Ted Masselink, Klaus Irmscher, Martin Albrecht
  • Suboxide sources, growth kinetics, n-type oxides: Oliver Bierwagen (MBE of n-type oxides)
  • P-n-devices: Holger von Wenckstern (associated member, University Leipzig)
  • NiO interaction with organics: external collaborator
  • (BaSnO3 substrates): Matthias Bickermann


The Research Team


Melanie Budde
PhD student

Melanie Budde was born in Hannover, Germany and studied Nanotechnology with a focus on semiconductor technology, physics of nanostructures and surfaces there between 2010 and 2016. Her PhD thesis is on the MBE growth and doping of p-type oxides. She sees GraFOx as an opportunity to continue her research in oxides using MBE growth combined with the chance to work in an interdisciplinary environment.


Project lead

If you have queries about the project, please contact the PI:
Oliver Bierwagen, Paul-Drude-Institut




Paul-Drude-Institut für
Leibniz-Insitut im Forschungsverbund Berlin e.V.
Hausvogteiplatz 5-7
10117 Berlin, Germany 

The Leibniz ScienceCampus GraFOx is a network of two Leibniz institutes, two universities and one institute of the Max Planck Society. The Network is based in Berlin, Germany.