Semiconducting oxides

Oxides are among the materials with the widest tunability of physical properties. Spanning insulators, semiconductors, metallic conductors and superconductors, magnetic materials, ferro-/antiferro- and other dielectrics, oxides are a materials class with high potential for a new generation of electronic devices for energy and sensing applications.


Traditionally, oxides have been synthesized by pulsed laser deposition or sputtering, which both have drawbacks in terms of material quality. A higher material quality can be achieved by molecular beam epitaxy (MBE), which is the growth method used by us.


Our research aims at exploring the properties of semiconducting oxides at the materials limit, equally taking into account the understanding of the growth thermodynamics and kinetics as well as the materials application perspective. Providing samples for (international) collaborations is an important part of our scientific culture. To date, our materials portfolio comprises the n-type oxides (Ga,In,Al)2O3, SnO2, the perovskites BaSnO3 and LaInO3, as well as the p-type oxides SnO and (the antiferromagnet) NiO. Out of these SnO2, NiO, and In2O3 are frequently used in conductometric gas sensing—an application whose fundamental investigation together with external collaborators greatly benefits from our well-defined samples. Energy-efficient power electronics as well as solar-blind UV sensing are further important applications, both of which are foreseen to profit tremendously from the ultra-wide bandgap semiconductor Ga2O3 and its solid solutions with In2O3 and Al2O3.


Embedded in the Berlin-based Leibniz ScienceCampus „Growth and fundamentals of oxides for electronic applications“ (GraFOx), led by PDI, our activities are currently divided into the following projects:


Selected Publications

8 Author P. Mazzolini , A. Falkenstein , C. Wouters , R. Schewski , T. Markurt , Z. Galazka , M. Martin , M. Albrecht , O. Bierwagen

Substrate-orientation dependence of β-Ga2O3 (100), (010), (001), and (ˉ201) homoepitaxy by indium-mediated metal-exchange catalyzed molecular beam epitaxy (MEXCAT-MBE)

Source APL Mater. , 8 , 011107 ( 2020 )
DOI : 10.1063/1.5135772 | Download: PDF | 3156 Cite : Bibtex RIS
P. Mazzolini, A. Falkenstein, C. Wouters, R. Schewski, T. Markurt, Z. Galazka, M. Martin, M. Albrecht, and O. Bierwagen

7 Author G. Hoffmann , M. Budde , P. Mazzolini , O. Bierwagen

Efficient suboxide sources in oxide molecular beam epitaxy using mixed metal + oxide charges: The examples of SnO and Ga2O

Source APL Mater. , 8 , 031110 ( 2020 )
DOI : 10.1063/1.5134444 | Download: PDF | 3152 Cite : Bibtex RIS
G. Hoffmann, M. Budde, P. Mazzolini, and O. Bierwagen

6 Author C. Golz , Z. Galazka , J. Lähnemann , V. Hortelano , F. Hatami , W.T. Masselink , O. Bierwagen

The electrical conductivity tensor of beta-Ga2O3 analyzed by van der Pauw measurements: Inherent anisotropy, off-diagonal element, and the impact of grain boundaries

Source Phys. Rev. Mater. , 3 , 124604 ( 2019 )
DOI : 10.1103/physrevmaterials.3.124604 | Download arXiv: | 3121 Cite : Bibtex RIS
C. Golz, Z. Galazka, J. Lähnemann, V. Hortelano, F. Hatami, W.T. Masselink, and O. Bierwagen

5 Author C.E. Simion , F. Schipani , A. Papadogianni , A. Stanoiu , M. Budde , A. Oprea , U. Weimar , O. Bierwagen , N. Barsan

Conductance Model for Single-Crystalline/Compact Metal Oxide Gas Sensing Layers in the Non-Degenerate Limit: Example of Epitaxial SnO2(101)

Source ACS Sens. , 4 , 2420 ( 2019 )
DOI : 10.1021/acssensors.9b01018 | Download arXiv: 2010.02962 | 3119 Cite : Bibtex RIS
C.E. Simion, F. Schipani, A. Papadogianni, A. Stanoiu, M. Budde, A. Oprea, U. Weimar, O. Bierwagen, and N. Barsan

4 Author M. Budde , C. Tschammer , P. Franz , J. Feldl , M. Ramsteiner , R. Goldhahn , M. Feneberg , N. Barsan , A. Oprea , O. Bierwagen

Structural, optical, and electrical properties of unintentionally doped NiO layers grown on MgO by plasma-assisted molecular beam epitaxy

Source J. Appl. Phys. , 123 , 195301 ( 2018 )
DOI : 10.1063/1.5026738 | Download: PDF | 3016 Cite : Bibtex RIS
M. Budde, C. Tschammer, P. Franz, J. Feldl, M. Ramsteiner, R. Goldhahn, M. Feneberg, N. Barsan, A. Oprea, and O. Bierwagen

3 Author Z. Cheng , M. Hanke , P. Vogt , O. Bierwagen , A. Trampert

Phase formation and strain relaxation of Ga2O3 on various sapphire orientations as studied by synchrotron-based x-ray diffraction

Source Appl. Phys. Lett. , 111 , 162104 ( 2017 )
DOI : 10.1063/1.4998804 | Download: PDF | 2948 Cite : Bibtex RIS
Z. Cheng, M. Hanke, P. Vogt, O. Bierwagen, and A. Trampert

2 Author P. Vogt , O. Brandt , H. Riechert , J. Lähnemann , O. Bierwagen

Metal-exchange catalysis in the growth of sesquioxides: towards heterostructures of transparent oxide semiconductors

Source Phys. Rev. Lett. , 119 , 196001 ( 2017 )
DOI : 10.1103/PhysRevLett.119.196001 | Download: PDF | 2925 Cite : Bibtex RIS
P. Vogt, O. Brandt, H. Riechert, J. Lähnemann, and O. Bierwagen

1 Author J. Rombach , A. Papadogianni , M. Mischo , V. Cimalla , L. Kirste , O. Ambacher , T. Berthold , S. Krischok , M. Himmerlich , Sören Selve , O. Bierwagen

The role of surface electron accumulation and bulk doping for gas-sensing explored with single-crystalline In2O3 thin films

Source Sens. Actuators B Chem. , 236 , 909 ( 2016 )
DOI : 10.1016/j.snb.2016.03.079 | 2784 Cite : Bibtex RIS
J. Rombach, A. Papadogianni, M. Mischo, V. Cimalla, L. Kirste, O. Ambacher, T. Berthold, S. Krischok, M. Himmerlich, Sören Selve, and O. Bierwagen


Dr. Lutz Geelhaar

Head of Department

+49 30 20377-359