Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 40: Impurities / Amorphous Semiconductors
HL 40.3: Vortrag
Dienstag, 27. März 2012, 12:00–12:15, EW 015
Evidence for Fe2+ in Wurtzite Coordination: Iron Doping Stabilizes ZnO Nanoparticles — •Jianping Xiao1,2, Agnieszka Kuc2, Suman Pokhrel3, Marco Schowalter4, Satyam Parlapalli4, Andreas Rosenauer4, Thomas Frauenheim1, Lutz Mädler3, Lars Pettersson5, and Thomas Heine2 — 1Bremen Centre for Computational Materials Science, Bremen, Germany — 2School of Engineering and Science, Jacobs University Bremen, Germany — 3IWT Foundation Institute of Materials Science, Bremen, Germany — 4Institute for Solid State Physics, Bremen, Germany — 5Stockholm University, Stockholm, Sweden
First-principles calculations are used to investigate the structural and electronic properties of Fe-doped ZnO nanoparticles. Based on extensive validation studies surveying various density functionals, the hybrid functional PBE0 is employed to calculate the structures, formation energies, and electronic properties of Fe in ZnO with Fe concentrations of 6.25, 12.5, and 18.75 at%. Substitution of Zn by Fe, zinc vacancies, and interstitial oxygen defects is studied. High-resolution inner-shell electron energy loss spectroscopy measurements and X-ray absorption near-edge structure calculations of Fe and O atoms are performed. The results show that Fe-doped ZnO nanoparticles are structurally and energetically more stable than the isolated FeO(rocksalt) and ZnO (wurtzite) phases. The Fe dopants do not significantly alter the host ZnO lattice parameters. Simulations of the absorption spectra demonstrate that Fe2+ dominates in the Fe-doped ZnO nanoparticles reported recently, whereas Fe3+ is present only as a trace.