Phase Transitions at the Mn/ZnO (0001) Interface Probed by High Energy X-ray Spectroscopies

Phase transitions occurring at the Mn/ZnO interface upon annealing are probed in situ by high-energy X-ray: photoelectron and absorption spectroscopies. A thin Mn film (∼1 nm) is grown on the (0001̅) surface of a ZnO single crystal. Upon annealing to progressively higher temperature ranging from 575 to 800 K, various Mn phases form successively. At first, the Mn film oxidizes and a MnO layer forms on top of the surface. Then, while Mn atoms diffuse deeper into the bulk of ZnO, Zn y Mn 3– y O 4 starts to form. Finally, at the highest annealing temperature, Mn appears to be substitutionally diluted at Zn sites within the ZnO lattice.