html page builder


C3.5 Growth mechanisms, adsorbates, surfactants, and doping during MOCVD
of β-Ga2O3, (In,Ga)2O3, and (Al,Ga)2O3



Overview of the research project:

Gallium oxide and its solid solutions with In2O3 and Al2O3 have recently attracted considerable interest as a promising material system for applications such as high power devices and solar blind UV photo detectors. Epitaxial growth of structurally perfect crystalline layers with defined doping is a prerequisite for exploiting their potential for device applications. The deposition of homoepitaxial Ga2O3 layers will be performed by using metal-organic vapor phase epitaxy (MOVPE). An essential requirement is the drastic reduction of the density of point and planar defects. At the same time, the effect of the latter on the electrical properties of the layers, such as conductivity and carrier mobility, has to be further investigated. The preparation of substrate surfaces with specific orientations and without any surface damage also plays an important role in the growth of high quality epitaxial layers and needs additional development.

The focus is on the study of the effects of the growth parameters and the nature of the donors on the electrical properties of the layers. Another point of interest is focused on the growth of β-Ga2O3 homoepitaxial layers on different oriented substrates and on substrates with optimized off-orientations in [001] direction and the investigation of their influence on the generation of planar- and point defects in the layers.


Major accomplishments expected:

  • Investigation of the morphology and defect features of the β-Ga2O3 substrate surface as result of chemical and thermal treatment and study of defects generated at the interface substrate-layer during the first stages of growth.
  • Growth of β-Ga2O3 layers with tuned n-type conductivity, by using silicon as donor. The focus will be on the study of the effects of the growth parameters and the nature of the donor on the electrical properties of the layers.
  • Delivering of β-Ga2O3 layers with high structural perfection and optimized n-type conductivity and carrier mobility for device engineering.
  • Increasing the band gap of β-Ga2O3 beyond 4.8 eV growth experiments with Al will be performed to grow (Al,Ga)2O3 ternary layers. The substitution of gallium in β-Ga2O3 by aluminum allows to tune the elastic strain in the layers due to lattice mismatch. The influence of the substitutional atoms on the crystalline structure and defect generation in the layers is studied in detail by HR-XRD and HR-TEM investigations.


Collaboration with partners in the project:

  • Bulk crystals grown by Czochralski method (C3)
  • TEM and electrical characterization (C4)
  • Study of surface dynamics (C2)
  • Study of the band alignment in heterostructures (C4)
  • Device (MOSFET, HEMT) fabrication and characterization (FBH)

The Research Team


Andreas Popp

Andreas Popp  

Andreas Popp studied physics at the Brandenburg University of Technology and received his PhD degree in 2017. In his doctoral thesis, which he did at the Helmholtz-Zentrum Berlin, he focused on the electronic structure and morphology of chalcopyrite thin layers grown heteroepitaxially by MBE. In December 2017 he joined the Group of Günter Wagner as a Post-Doc at the Leibniz Institute for Crystal Growth (IKZ). He is responsible for the growth of Ga2O3 layers by MOVPE.


Project lead

If you have queries about the project, please contact the PI:
Günter Wagner, Institut für Kristallzüchtung


Logo Leibniz-Gemeinschaft

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


Imprint | Data Protection


Kai Hablizel

Paul-Drude Institut für Festkörperelektronik (PDI)
Leibniz-Institut im Forschungsverbund Berlin e.V.
Tel.: +49 30 20377-342




Prof. Dr. Henning Riechert, PDI

Scientific Coordinator:

Dr. Oliver Bierwagen, PDI
Dr. Martin Albrecht, IKZ