Transmission electron microscopy investigation of ZnFeO/ZnO multilayered dilute magnetic semiconductor

ZnFeO/ZnO multilayers which are candidate dilute magnetic semiconductors, were investigated by high-resolution transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), and selected area electron diffraction analysis (SAED). The multilayers were fabricated by a sputtering method and had different ZnFeO layers thicknesses ranging from 0.34 to 2.28 nm. In the case of the as-deposited ZnFeO/ZnO multilayer, the main ZnO phase with the Fe2O3 phase was detected by TEM?SAED analysis from the cross-sectional view of the multilayer. On the other hand, in the case of the ZnFeO/ZnO multilayer after annealing at 773 K, the layer structure collapsed and Fe-rich grains were formed in the surface region. Moreover, it was revealed that the annealed multilayer exhibits the ZnO phase and the ZnFe2O4 or Fe3O4 phase.