title: A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials.
abstract: Numerous applications in optoelectronics require electrically conducting materials with high optical transparency over the entire visible light range. A solid solution of indium oxide and substantial amounts of tin oxide for electronic doping (ITO) is currently the most prominent example for the class of so-called TCOs (transparent conducting oxides). Due to the limited, natural occurrence of indium and its steadily increasing price, it is highly desired to identify materials alternatives containing highly abundant chemical elements. The doping of other metal oxides (e.g., zinc oxide, ZnO) is a promising approach, but two problems can be identified. Phase separation might occur at the required high concentration of the doping element, and for successful electronic modification it is mandatory that the introduced heteroelement occupies a defined position in the lattice of the host material. In the case of ZnO, most attention has been attributed so far to n-doping via substitution of Zn(2+) by other metals (e.g., Al(3+)). Here, we present first steps towards n-doped ZnO-based TCO materials via substitution in the anion lattice (O(2-) versus halogenides). A special approach is presented, using novel single-source precursors containing a potential excerpt of the target lattice 'HalZn·Zn3O3' preorganized on the molecular scale (Hal = I, Br, Cl). We report about the synthesis of the precursors, their transformation into halogene-containing ZnO materials, and finally structural, optical and electronic properties are investigated using a combination of techniques including FT-Raman, low-T photoluminescence, impedance and THz spectroscopies.
authors.affiliation: Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Lehr
authors.affiliation: ICN2 Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, 08193 Bellaterra (Barcelona), Spain.
authors.forename: Markus R
authors.initials: MR
authors.lastname: Wagner
authors.affiliation: Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Flock
authors.affiliation: ICN2 Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, 08193 Bellaterra (Barcelona), Spain.
authors.forename: Julian S
authors.initials: JS
authors.lastname: Reparaz
authors.affiliation: ICN2 Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, 08193 Bellaterra (Barcelona), Spain ; Catalan Institute of Research and Advanced Studies (ICREA), Barcelona 08010, Spain.
authors.forename: Clivia M
authors.initials: CM
authors.lastname: Sotomayor Torres
authors.affiliation: Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Klaiber
authors.affiliation: Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dekorsy
authors.affiliation: Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Polarz
keywords: chemical doping; metal oxides; semiconductor nanoparticles; single-source precursors