Inversion domain network stabilization and spinel phase suppression in ZnO

The development of inversion domain networks consisting of basal-plane and pyramidal-plane inversion domain boundary (b-IDB and p-IDB) interfaces within grains in Sn-Al dual-doped ZnO (Zn0.98Sn0.01Al0.01O) polycrystalline ceramics has been confirmed using transmission electron microscopy. The atomic structure of the b-IDB and p-IDB interfaces has been analyzed using atomic-resolution scanning transmission electron microscopy. The localization of Sn and Al at the respective sites of the b-IDBs and p-IDBs was confirmed by energy-dispersive X-ray spectroscopy. In contrast to Sn or Al single-dopant addition to ZnO, which results in the formation of spinel phase precipitates without the development of inversion domain networks, Sn-Al dual-doping caused the suppression of spinel phase formation and the formation of monophasic inversion domain networks composed of RMO3(ZnO)(n) homologous phase compound members, where R and M represent dopants substituting at the b-IDB and p-IDB sites, with a general formula of SnAlO3(ZnO)(n). The results of this study demonstrate that the formation of inversion domain networks in ZnO-based ceramics can be stabilized via multiple-dopant addition. This finding has potential implications for the modification of the bulk or nanoscale properties based on the choice of the specific dopants, R and M, the control of the ratio R:M and the value of n in the RMO3(ZnO)(n) homologous phase compound members constituting the inversion domain networks.