过渡金属硫属化合物具有优异的物理化学特性，在光/电子器件、忆阻器、可再生能源存储与转换等方面具有广阔的应用前景，是继石墨烯之后升起的材料新星。MoS2是过渡金属硫属化合物家族中研究最为广泛和深入的代表材料，目前MoS2的制备主要包括自上而下与自下而上两种思路，其中化学气相沉积法（CVD）由于其丰富可调的实验参数而被认为是获得层厚可控、大畴区高质量MoS2的有效方法。c面蓝宝石由于具有平整稳定的表面特性和适配的晶格常数常被选作生长MoS2的绝缘衬底，近期报道的MoS2在c面蓝宝石上的取向生长使该生长体系吸引了更多的研究兴趣。 本文采用氧辅助的低压化学气相沉积系统进行MoS2取向生长行为的研究，发现氧气在该体系下具有提供反应源、促进生长和刻蚀小尺寸成核点的多重作用，研究结果发现S粉温度、O2含量、生长温度等多种可调参数本质上通过影响S/Mo值来调控取向生长行为。最后结合玻璃中Na元素对MoS2生长的催化作用，本文获得了最大畴区10.-.20 μm的取向生长结果。大面积取向生长的实现对减少畴区边界、保证器件性能具有重要意义。

Transition metal dichalcogenides, a rising material nova following graphene, possess many excellent physical and chemical properties, which bring them broad applications including optical/electronic devices, memristorr, renewable energy storage/conversions and other aspects. MoS2 is the most extensively researched material in transition metal dichalcogenides. The preparation of MoS2 mainly includes two typical routes: top-down and bottom-up methods. Chemical vapor deposition (CVD) is one of the bottom-up approaches. Due to the abundant adjustable experimental parameters, CVD is considered to be an effective method to achieve controlled layer thickness, large domain size and high quality. C-sapphire is often selected as an insulating substrate for MoS2 growth due to its smooth and stable surface characteristics as well as its adaptive lattice constant. Recently, many groups have reported the orientated growth of MoS2 on c-sapphire, making the growth system more attractive. Herein, we used the oxygen-assisted low pressure chemical vapor deposition method to achieve oriented growth of MoS2 on sapphire substrate. We found that the oxygen, introduced in the system, has multiple functions including a source of the reaction, promoting the grow process and etching the small sized nuclei. Besides, the temperature of sulfur, the O2 content, the growth temperature and many other adjustable parameters can essentially control this oriented growth behavior by influencing the S/Mo ratios. Based on the catalysis of Na in glass, the size of oriented MoS2 domain may reach 10 - 20 μm. This realization of large area oriented growth is of great significance to decrease the number of grain boundaries and ensure the performance of devices.