Syntheses and Single-Crystal Data of Homologous Compounds, In2O3(ZnO)m (m = 3, 4, and 5), InGaO3(ZnO)3, and Ga2O3(ZnO)m (m = 7, 8, 9, and 16) in the In2O3-ZnGa2O4-ZnO System

Abstract

Homologous compounds, In2O3(ZnO)m (m ≥ 3), (InGaO3)2 ZnO, InGaO3(ZnO)m (m ≥ 1), and Ga2O3(ZnO)m (m ≥ 7) phases (m = natural number) in the In2O3-ZnGa2O4-ZnO system were synthesized at 1150-1550°C from In2O3, Ga2O3, and ZnO powders. The homologous compounds with smaller m are synthesized as temperature is elevated higher. Single crystals of In2O3(ZnO)m (m = 3, 4, and 5), InGaO3(ZnO)3, and Ga2O3(ZnO)m (m ≥ 7, 8, 9, and 16) were grown by means of solid-state reactions in the mixtures of the starting compound powders with mixing ratio of In2O3:ZnO = 1:m at 1550°C, In2O3:Ga2O3:ZnO = 1:1:6 at 1550°C, and Ga2O3:ZnO = 1:m (in a mole ratio) at 1450-1550°C. The crystal data determined by means of a Weissenberg camera are as follows: In2O3(ZnO)3; a = 3.34 Å; and c = 42.6 Å; In2O3(ZnO)4, a = 3.33 Å and c = 33.5 Å; In2O3(ZnO)5, a = 3.32 Å and c = 58.4Å; and InGaO3(ZnO)3, a = 3.29Å and c = 41.8Å. The crystal data determined by means of a single-crystal X-ray diffractometer are as follows: Ga2O3(ZnO)7, a = 3.2512(1) Å, b = 19.654(3)Å, and c = 27.754(4)Å; Ga2O3(ZnO)8, a = 3.2497(1)Å, b = 19.682(3)Å, and c = 30.684(3)Å; Ga2O3(ZnO)9, a = 3.2520(1)Å, b = 19.707(4)Å, and c = 33.603(5)Å; and Ga2O3(ZnO)16, a = 3.2534(1)Å, b = 19.764(3)Å, and c = 54.208(5)Å, orthorhombic crystal system in Cmcm space group (No. 63). In2O3(ZnO)m and InGaO3(ZnO)m belong to 3̄m for m = odd or P 63/mmc for m = even, and their lattice constants are given in a hexagonal form. The crystal data for In2O3(ZnO)m, InGaO3(ZnO)m, and Ga2O3(ZnO)m are discussed based upon the wurtzite-type crystal structure.