Holger Beh
Holger Beh University of Freiburg - IMTEK Department of NanotechnologyRoom 103-01-097Georges-Koehler-Allee 10379110 FreiburgPhone: +49 (0)761 203-7101 |
Research project
Transparent conductive oxides (TCOs) play an important role as transparent top contacts in energy harvesting via solar cells and for light emitting diodes. Since indium tin oxide (ITO) is rather expensive and rare, cheaper and more abundant alternatives are needed. Usually, zinc oxide with added aluminum (AZO) is used for most TCO applications. The deposition via sputtering, however, includes problems concerning impact energy, layer uniformity and vacuum requirements. These problems can be overcome by the use of pure zinc oxide (ZnO) deposited by atomic layer deposition (ALD). The reason for ALD ZnO being conductive without added aluminum is not clear yet. Possible candidates for the conductivity mechanism are e.g. oxygen defects, hydrogen interstitials and zinc defects.
In our project, ALD-ZnO layers are characterized by various methods to eventually obtain a complete and consistent image of the conductivity mechanism in ALD ZnO in order to optimize the fabrication parameters for maximum conductivity as well as possible improved long-term stability.
Curriculum Vitae
Practical and Scientific Experience
2014 - Today | University of Freiburg Department of Nanotechnology PhD-Student |
2012 - 2014 | Fraunhofer IAF Research Assistant |
2011 - 2012 | Max Planck Institute MPI-IE Research Assistant |
Studies
2011 - 2013 | University of Freiburg Faculty of Physics, M.Sc. |
2008 - 2011 | University of Freiburg Faculty of Physics, B.Sc. |
Publications
Paper
- Laube J, Nübling D, Beh H, Gutsch S, Hiller D, Zacharias M
*Resistivity of atomic layer deposition grown ZnO: The influence of deposition temperature and post-annealing* 2016 /Thin Solid Films/, Band: 603, Seite: 377,
DOI: 10.1016/j.tsf.2016.02.060 - Beh H, Hiller D, Laube J, Gutsch S, Zacharias M
*Deposition temperature dependence and long-term stability of the conductivity of undoped ZnO grown by atomic layer deposition*
2017 /J Vac Sci Technol A/, Band: 35, Nummer: 1, Seite: 01B127,
DOI: 10.1116/1.4972466 - Beh H, Hiller D, Bruns M, Welle A, Becker H, Berghoff B, Suergers C, Merz R, Zacharias M
*Quasi-metallic behavior of ZnO grown by atomic layer deposition: The role of hydrogen*
2017 /J Appl Phys/, Band: 122, Nummer: 4, ACCEPTED
Conference contributions:
- H. Beh, D. Hiller, M. Bruns, A. Welle, H.-W. Becker, B. Berghoff, C.
Sürgers, M. Zacharias: Quasi-metallic ZnO grown by atomic layer
deposition (ALD): understanding the origin of conductivity.
/Presentation, /E-MRS Fall Meeting 2017, Warsaw, 18-21 September 2017
(ACCEPTED) - H. Beh, D. Hiller, M. Bruns, A. Welle, H.-W. Becker, M. Zacharias:
Maximizing the conductivity of ALD ZnO. /Presentation,/ //E-MRS Fall
Meeting 2017, Warsaw, 18-21 September 2017 (ACCEPTED) - H. Beh, D. Hiller, B. Berghoff, M. Zacharias: ZnO grown by atomic layer
deposition: A good TCO for future applications?. /Poster/, E-MRS Fall
Meeting 2017, Warsaw, 18-21 September 2017 (ACCEPTED)