Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
ACS Appl Mater Interfaces. 2012 Oct 24;4(10):5333-7. doi: 10.1021/am301271k. Epub 2012 Oct 1.
High-quality m-plane orientated ZnO films have been successfully grown on m-plane sapphire by using radio frequency magnetron sputtering deposition. The introduction of a nanometer-thick, low-temperature-grown ZnO buffer layer effectively eliminates inclusions of other undesirable orientations. The structure characteristics of the ZnO epi-layers were thoroughly studied by synchrotron X-ray scattering and transmission electron microscopy (TEM). The in-plane epitaxial relationship between ZnO and sapphire follows (0002)(ZnO) [parallel] (112[overline]0)(sapphire) and (112[overline]0)(ZnO) [parallel] (0006)(sapphire) and the ZnO/sapphire interface structure can be described by the domain matching epitaxy along the 112[overline]0 direction. The vibrational properties of the films were investigated by polarization dependent micro-Raman spectroscopy. Both XRD and micro-Raman results reveal that the obtained m-ZnO layers are under an anisotropic biaxial strain but still retains a hexagonal lattice.
高品质的 m 面取向 ZnO 薄膜已成功地通过射频磁控溅射沉积在 m 面蓝宝石上生长。通过引入一层纳米厚度的低温生长 ZnO 缓冲层，有效地消除了其他不理想取向的夹杂。利用同步辐射 X 射线散射和透射电子显微镜（TEM）对 ZnO 外延层的结构特征进行了深入研究。ZnO 与蓝宝石之间的面内外延关系为 (0002)(ZnO) [平行] (112[overline]0)(蓝宝石) 和 (112[overline]0)(ZnO) [平行] (0006)(蓝宝石)，并且 ZnO/蓝宝石界面结构可以通过沿 112[overline]0 方向的畴匹配外延来描述。通过偏振相关微拉曼光谱研究了薄膜的振动特性。XRD 和微拉曼结果都表明，所得到的 m-ZnO 层处于各向异性双轴应变下，但仍保持六方晶格。
