title: Control of epitaxial relationships of ZnO/SrTiO3 heterointerfaces by etching the substrate surface.
abstract: Wurtzite ZnO thin films with different epitaxial relationships are obtained on as-received and etched (001), (011), and (111) SrTiO3 (STO) by metal-organic chemical vapor deposition (MOCVD). ZnO films exhibit nonpolar (1120) orientation with in-plane orientation relationship of <0001>ZnO//<110>STO on as-received (001) STO, and polar c-axis growth with <1100>ZnO//<110>STO on etched (001) STO substrates. ZnO films change from polar (0001) to semipolar (1012) oriented on as-received and etched (011) STO. On as-received and etched (111) STO, ZnO films show the same growing direction of polar (0001), but different in-plane orientations with 30° rotation. The change of epitaxial relationship of ZnO films on as-received and etched (001), (011), and (111) STO substrates is accompanied with the increase of lattice mismatch, decrease of bond density, and increase of substrate surface roughness. In other words, the epitaxial relationships of ZnO/STO heterointerfaces can be controlled by etching the substrates. These results show that polar, nonpolar, and semipolar ZnO films for different applications can be grown epitaxially on STO substrates by MOCVD.
authors.affiliation: Key Laboratory of Semiconductor Material Science, Institute of Semiconductors, Chinese Academy of Science, P,O, Box 912, Beijing, 100083, People's Republic of China. yhchen@red.semi.ac.cn.
authors.forename: Caihong
authors.initials: C
authors.lastname: Jia
authors.forename: Yonghai
authors.initials: Y
authors.lastname: Chen
authors.forename: Xianglin
authors.initials: X
authors.lastname: Liu
authors.forename: Shaoyan
authors.initials: S
authors.lastname: Yang
authors.forename: Weifeng
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhanguo
authors.initials: Z
authors.lastname: Wang