Structure and optical properties of [In1−2xSnxZnx]GaO3(ZnO)m

• New Oxides [In1−2xSnxZnx]GaO3(ZnO)m (m=1, 2) with IGZO type structure.
• Sn and Zn substitute for In at octahedral sites.
• Crystal structures were characterized by single crystal X-ray diffraction.
• Optical band gap energies were determined by UV–vis spectroscopy.

Compounds of [In1−2xSnxZnx]GaO3(ZnO)1 (x≤0.22) and [In1−2xSnxZnx]GaO3(ZnO)2 (x≤0.42) were prepared by solid state processing proving a substantial solid solution of Sn in the layered compounds InGaO3(ZnO)m (m=1, 2). Single crystal X-ray diffraction of the compounds reveals two In3+ ions to be substituted by one Sn4+ and one Zn2+ at the octahedral layer preserving the average charge of +3 at these sites. The substitution does not lead to an ordering of the ions but proves for the first time that the octahedral site can be occupied by different ions while all characteristics of the layered structures remain unchanged. Consequences of indium substitution are (i) decrease of the a axis compared to InGaO3(ZnO)m according to smaller ionic radii of Sn4+ and Zn2+ compared to In3+ and (ii) shift of the optical band gap to higher energies shown by UV–vis measurements.

Substitution limits of indium in InGaO3(ZnO)m (IGZO) by Sn and Zn are studied for m=1, 2 by single crystal X-ray diffraction and micro-chemical analysis.Figure optionsDownload as PowerPoint slide