Identification of a secondary phase Ga2O3(ZnO)m in Ga-doped ZnO thermoelectric materials by a (3 + 1)-dimensional superspace model

A unified structure model for the homologous compounds Ga2O3(ZnO)m in (3 + 1)-dimensional superspace was modified by refinements for samples of Ga2O3:ZnO = 1:n (n = 15, 23, 28, 33, 38). The first-order sine terms in the modulation functions decreased with increasing phase index m. The diffraction intensities of the thermoelectric material Ga2O3:ZnO = 1:98 were best fitted by a two-phase model containing the wurtzite structure (Ga-doped ZnO) and the homologous compound Ga2O3(ZnO)s, where s = 38.