Defect Clustering and Ordering in Zn-Doped TiO₂ upon Solution Annealing

TiO2−ZnO powders in a molar ratio of 92:8 were subject to solution annealing via a reactive sintering route prior to X-ray diffraction and transmission electron microscopic studies. Charge-compensating defect clusters and planar faults predominantly parallel to (121) and (132) planes, analogous to the crystallographic shear of nonstoichiometric TinO2n−1 with specific extent of oxygen vacancies, were formed in the Zn-doped TiO2 of the rutile-type structure when quenched from 1300 °C in air. Upon annealing at 900 °C, an additional phase with 3x(101) commensurate superstructure was formed by an ordering process and Guinier−Preston zones parallel to (100) and (010) were exsolved via anisotropic lattice diffusion.