Yevgen Syryanyy
supervisor: Iraida Demchenko
The electronic structure of ZnO:Yb epitaxial layers grown on GaN/sapphire substrates was studied using X-ray absorption spectroscopy at the Zn L3, O K and Yb M5 edges at Solaris light source. Knowing that the ZnO crystallizes in an anisotropic wurtzite structure, the linear polarization of synchrotron radiation was exploited to estimate the influence of the crystal structure anisotropy on the distribution of the local density of states at the site of Zn and O. The calculated partial density of states describes the observed anisotropy in the measured spectra. Influence of the core–hole effect on the analyzed absorption spectra was verified.
Acknowledgements: We acknowledge National Synchrotron Radiation Centre SOLARIS for provision of synchrotron radiation facilities, and we thank the beamline "PEEM/XAS" team for assistance; and dr R. Ratajczak from National Centre for Nuclear Research (Otwock, Poland) for assist in samples preparation. The work was partially supported by the Interdisciplinary Centre for Mathematical and Computational Modelling (ICM) at University of Warsaw, Poland (G 3557) and National Science Centre, Poland (UMO-2020/39/B/ST5/03580). The samples growth was co-financed by international project supported by the Polish Ministry of Science and Higher Education (3846/HZDR/2018/0) and Helmholtz-Zentrum Dresden-Rossendorf (17000941-ST).