Cobalt doping as the controlling factor of oxygen diffusivity in ZnO by more than four orders of magnitude

摘要

Oxygen diffusivity in ZnO ceramics doped with cobalt was investigated using an isotope tracer method. The oxygen isotope (~(18)O) was introduced by ~(18)O/~(16)O exchange annealing in an ~(18)O_2 atmosphere, and the depth profile of the ~(18)O concentration was analyzed by secondary ion mass spectrometry. The results show that oxygen diffusivity in ZnO steeply increases with increasing Co concentration. In fact, the bulk oxygen diffusivity in 15 mol% Co-doped ZnO was four orders of magnitude greater than that of nominally non-doped ZnO. Oxygen diffusivity at grain boundaries was also enhanced by Co-doping.