Structure of Ga₂O₃(ZnO)₆: a member of the homologous series Ga₂O₃(ZnO) _m

Abstract

The structure of Ga(2)O(3)(ZnO)(6) was determined using single-crystal X-ray diffraction techniques in the space group Cmcm. The metal ion sublattice resembles some of the Zn ions in the wurtzite ZnO structure. The oxygen ion sublattice in Ga(2)O(3)(ZnO)(6) also resembles some of the O ions in ZnO. Structural relationships between Ga(2)O(3)(ZnO)(6) and ZnO are discussed, illustrating the process for obtaining the centrosymmetric Ga(2)O(3)(ZnO)(6) structure from the noncentrosymmetric ZnO. Structures of phases in the homologous series Ga(2)O(3)(ZnO)(m) are predicted on the basis of the structural data for Ga(2)O(3)(ZnO)(6). The structures of even m are constructed by simply extending the structure units seen in Ga(2)O(3)(ZnO)(6), while those of odd m consist of structure units which are of different types from those used for even m.

Multi-component transparent conducting oxides: progress in materials modelling

“…Experimental characterisation using XRD has found that GZO crystallizes in orthorhombic structures with space group Cmcm for n > 1, and the 'normal' cubic spinel structure for m = n = 1. The internal structural parameters (atomic positions) have been reported only for m = 1, n = 1, 6 [103]; however, it is important to note that the atomic number of Ga and Zn differs only by one unit, and hence, XRD alone cannot clearly distinguish between the Ga and Zn site occupation, i.e. it was assumed that Ga atoms occupy specific cation sites, while Zn occupy the remaining sites.…”

“…it was assumed that Ga atoms occupy specific cation sites, while Zn occupy the remaining sites. The pioneering work reported by Michiue et al [103] provided a basis for the understanding of the atomic structure of GZO compounds; however, a number of questions remained to be solved at that time.…”

“…The exact temperature required depends on the composition and the desired products [99][100][101][102][103]. A large number of syntheses have been performed; and crystal structures were first reported for R = In and Ga, with different M .…”

“…[99,[111][112][113]122] In contrast to the In atoms in IZO which is 6-fold coordinated, Ga atoms may exist at low coordination sites. For example, in the GZO structure proposed by Michiue et al [103] there are two cation sites (called M 8 and M 7 in Ref. 103), which are 5-and 4-fold coordinated and were assumed to partially occupied by Zn atoms.…”

“…For example, in the GZO structure proposed by Michiue et al [103] there are two cation sites (called M 8 and M 7 in Ref. 103), which are 5-and 4-fold coordinated and were assumed to partially occupied by Zn atoms. We showed that the M 8 sites are empty and the M 7 sites are occupied by Ga atoms, while the remaining Ga atoms are distributed in 6-fold like sites.…”