Structural, Electrical, and Optical Properties of the Tetragonal, Fluorite-Related Zn0.456 In1.084 Ge0.460 O3
Abstract
We report the discovery of Zn0.456 In1.084 Ge0.460 O3 , 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, Ag6 GeSO8 , 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 In2 O3 , which is the host material for the current leading transparent conducting oxides. The structure of Zn0.456 In1.084 Ge0.460 O3 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 Zn0.456 In1.084 Ge0.460 O3 offers the potential for future studies to further understand carrier generation in -3 eV oxide semiconductors. © 2015 American Chemical Society.
Keywords
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