Phase Transitions at the Mn/ZnO (000(1)over-bar) Interface Probed by High Energy X-ray Spectroscopies

Abstract

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 (similar to 1 nm) is grown on the (000 (1) over bar) 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, ZnyMn3-yO4 starts to form. Finally, at the highest annealing temperature, Mn appears to be substitutionally diluted at Zn sites within the ZnO lattice.