Key Laboratory of Semiconductor Material Science, Institute of Semiconductors, Chinese Academy of Science, P,O, Box 912, Beijing, 100083, People's Republic of China.
Nanoscale Res Lett. 2013 Jan 10;8(1):23. doi: 10.1186/1556-276X-8-23.
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.
通过金属有机化学气相沉积（MOCVD），在原始和刻蚀的（001）、（011）和（111）SrTiO3（STO）上获得了具有不同外延关系的纤锌矿 ZnO 薄膜。在原始（001）STO 上，ZnO 薄膜呈现出非极性（1120）取向，具有面内取向关系<0001>ZnO//<110>STO，而在刻蚀的（001）STO 衬底上，具有极性 c 轴生长，<1100>ZnO//<110>STO。在原始和刻蚀的（011）STO 上，ZnO 薄膜从极性（0001）转变为半极性（1012）取向。在原始和刻蚀的（111）STO 上，ZnO 薄膜表现出相同的极性（0001）生长方向，但具有 30°旋转的不同面内取向。ZnO 薄膜在原始和刻蚀的（001）、（011）和（111）STO 衬底上的外延关系的变化伴随着晶格失配的增加、键密度的降低和衬底表面粗糙度的增加。换句话说，通过刻蚀衬底可以控制 ZnO/STO 异质界面的外延关系。这些结果表明，通过 MOCVD 可以在 STO 衬底上外延生长不同应用的极性、非极性和半极性 ZnO 薄膜。
