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利用脉冲激光沉积(PLD)技术在单晶硅衬底的非晶态SiO_2过渡层上外延生长了具有优良结晶品质和高度C轴取向性的LiNbO_3光波导薄膜。利用X射线衍射、高分辨电子显微镜和原子力显微镜等手段对LiNbO_3薄膜的结晶品质和C轴取向性等进行了系统的分析,基本确定了薄膜C轴外延生长的最佳沉积参数。非晶态SiO_2过渡层上的LiNbO_3薄膜由尺度约为150 nm×150 nm的四方柱状C轴取向的单晶畴紧密排列而成,并且具有陡峭的界面结构。棱镜耦合技术测量表明,激光可以被耦合到LiNbO_3薄膜中,形成TE和TM模式的光波导。此外,对于LiNbO_3薄膜在非晶过渡层上择优取向生长的物理机制和薄膜基底效应进行了初步探讨,提出其生长机制很可能符合光滑晶面上三维岛状成核生长的Volmer模式。
The LiNbO 3 optical waveguide film with excellent crystal quality and high C-axis orientation was epitaxially grown on the amorphous SiO 2 transition layer of single crystal silicon substrate by pulsed laser deposition (PLD). The crystal quality and C-axis orientation of LiNbO_3 thin films were systematically analyzed by X-ray diffraction, high-resolution electron microscopy and atomic force microscopy. The optimal deposition parameters for C-axis epitaxial growth were basically determined. The LiNbO_3 thin films on the amorphous SiO_2 transitional layer are closely arranged by the square C-axis aligned single-crystal domains with a size of about 150 nm × 150 nm and have a steep interface structure. Prism coupling measurements show that lasers can be coupled into LiNbO_3 films to form TE and TM mode optical waveguides. In addition, the physical mechanism of the preferred orientation growth of LiNbO_3 thin film on the amorphous transition layer and the substrate effect of the film are discussed, and the Volmer mode whose growth mechanism is likely to conform to the three-dimensional island nucleation growth on the smooth crystal face is proposed.