报告题目：Interfaces between hexagonal and cubic oxides and their growth orientation alternatives

报告人：周华 博士，深圳大学材料学院

时 间：2018年05月29日（周二）14:30

地 点：知新楼C座7楼量子报告厅C702

邀请人：颜世申 教授

摘要：

Multi-layer structure of functional materials often involves the integration of different crystalline phases. The film growth orientation thus frequently exhibits a transformation, owing to multiple possibilities caused by incompatible in-plane structural symmetry. Nevertheless, the detailed mechanism of the transformation has not yet been fully explored. Here, we report  the heteroepitaxially grown hexagonal ZnO films on cubic (001)-MgO substratesusing advanced scanning transition electron microscopy, X-ray diffraction and first principles calculations, revealing two distinct interface models of (001) ZnO / (001) MgO and (100) ZnO / (001) MgO. We have found that the structure alternatives are controlled thermodynamically by the nucleation, while kinetically by the enhanced Zn adsorption and O diffusion upon the phase transformation. Furthermore, this phenomena of growth alternative had also been found in the cubic SrTiO3 film grown on hexagonal (0001)-Al2O3 substrate by pulsed laser deposition method. This work not only provides a guideline for the interface fabrication with distinct crystalline phases, but also shows how polar and non-polar hexagonal ZnO films might be manipulated on the same cubic substrate.

References:

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3. Zhou Hua et al. Nature communications. 2017, 8, 1474.