Structural, Electrical, and Optical Properties of the Tetragonal, Fluorite-Related Zn0.456In1.084Ge0.460O3

K. Rickert (1) , N. Sedefoglu (1, 2) , S. Malo (3) , V. Caignaert (3) , H. Kavak (4) , K.R. Poeppelmeier (1)

1 Northwestern University [Evanston]
2 Osmaniye Korkut Ata University
3 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
4 Cukurova University

We report the discovery of Zn0.456In1.084Ge0.460O3, a material closely related to bixbyite. In contrast, however, the oxygen atoms in this new phase occupy 4 Wyckoff positions, which result in 4 four-coordinate, 24 six-coordinate (2 different Wyckoff positions), and 4 eight-coordinate sites as compared to the 32 six-coordinate (also 2 different Wyckoff positions) sites of bixbyite. This highly ordered material is related to fluorite, Ag6GeSO8, and -UO3 and is n-type with a bulk carrier concentration of 4.772 × 1014 cm-3. The reduced form displays an average room temperature conductivity of 99(11) S·cm-1 and an average optical band gap of 2.88(1) eV. These properties are comparable to those of In2O3, which is the host material for the current leading transparent conducting oxides. The structure of Zn0.456In1.084Ge0.460O3 is solved from a combined refinement of synchrotron X-ray powder diffraction and time-of-flight neutron powder diffraction and confirmed with electron diffraction. The solution is a new, layered, tetragonal structure in the I41/amd space group with a = 7.033986(19) Å and c = 19.74961(8) Å. The complex cationic topological network adopted by Zn0.456In1.084Ge0.460O3 offers the potential for future studies to further understand carrier generation in -3 eV oxide semiconductors. © 2015 American Chemical Society.

Mots clés: Carrier concentration; Complex networks; Energy gap; Fluorspar; Germanium; Single crystals; X ray powder diffraction; Zinc; Carrier generation; Oxide semiconductor; Room-temperature conductivity; Synchrotron X ray powder diffraction; Tetragonal structure; Time-of-flight neutron powder diffraction; Topological networks; Transparent conducting oxide; Optical properties; Anions; Materials; Chemical structure; Electrical conductivity; Cations

Domaines: Chimie; Cristallographie; Matériaux; Chimie théorique et/ou physique

K. Rickert, N. Sedefoglu, S. Malo, V. Caignaert, H. Kavak, et al.. Structural, Electrical, and Optical Properties of the Tetragonal, Fluorite-Related Zn0.456In1.084Ge0.460O3. Chemistry of Materials, 2015, 27 (14), pp.5072-5079. ⟨10.1021/acs.chemmater.5b01724⟩. ⟨hal-02184152⟩