Structure and non-equilibrium phase diagram of the co-sputtered and post-annealed Fe-ZnO system

X-ray diffraction and electron microscopic studies on co-sputtered Zn _1-xFe ₂O single crystalline films showed the solubility limit to be about X = 0.50 at 673 K. An increase of Fe greater than 0.50 resulted in the existence of Fe metal and (ZnFe)Fe ₂O ₄ spinel solid solution in a matrix of (ZnFe)O wurtzite solid solution below a substrate temperature of 573 K. Above a substrate temperature of 673 K., a ZnFe ₂O ₄ spinel phase rather than a Fe metal phase was seen. Annealing of as-sputtered films with a single phase of Zn _1-xFe _xO in air led to decomposition to the two-phase structure of Zn _1-xFe _xO wurtzite and ZnFe ₂O ₄ spinel and the decrease of the solubility limit of Fe in ZnO to about x = 0.11 at 873 K.