Dynamic observation on the functional metal oxide conversion behaviors in Fe3O4/ZnO heterostructures

Abstract

We directly observed the atomic diffusion process of bilayered Fe/ZnO transforming into a Fe3O4/ZnO heterostructure. Significantly, we suggested a unique two-step route in which Fe diffused along [0001](znO) via boundaries of ZnO and then reacted along [(1) over bar2 (1) over bar0](ZnO). The specific orientation relationship of [0001(]ZnO)//[11 (1) over bar ]Fe3O4 could be precisely controlled. In addition, the formation of a ZnO/Fe3O4 heterostructure can be tuned in terms of reaction depth by controlling the annealing time. This study provided a novel nanofabricated method to produce oriented metal oxide heterostructures while visualizing the atomic mechanism of metal oxide formation, which allows for further investigation of promising devices. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.