单层TMDC薄膜制备与异质结构光探测性能研究

With a direct band gap, monolayer semiconducting transition metal dichalcogenides (TMDC) have attracted significant interest among the two-dimensional (2D) crystals beyond graphene. Controlled synthesis of large-scale, uniform, and high-quality monolayer film is the key towards mass production of their optoelectronic devices. In this project, we propose the synthesis of monolayer semiconducting TMDC film by plasma enhanced chemical vapor deposition (PECVD) and the research on the wavelength tunable, high quantum efficiency photodectors based on their heterostructures.In detail, we will focus on MoS2 and WSe2, which are two representative materials of the TMDC family, and work on the following three aspects: (1) We will explore the optimized synthetic parameters with high crystalline quality and flexible-substrate compatible film growth capability. The growth mechanism will be elucidated. (2) Combined with crystal structure characterization, optical spectra analysis, and carrier mobility measurement based on field effect transistor, film quality of monolayer MoS2 and WSe2 will be systematically studied. (3) Through the investigation of photodetecting performance of atomically layer MoS2, WSe2 and their heterostructures, photoresponse mechanism will also be elucidated. More importantly, our work will pave the way towards better controlled synthesis of large-scale, high-quality atomically TMDC films and outstanding photodetecting performance based on their heterosturstures. our work will be a scientific reference for the fundamental research on 2D semiconducting TMDC and their optoelectronic devices.

单层过渡金属硫化物(TMDC)半导体因具有直接带隙，成为二维晶体材料研究的热点，而大面积均匀、高质量单层薄膜的可控制备是实现其规模化光电器件的关键。项目提出以等离子增强化学气相沉积(PECVD)制备单层TMDC半导体薄膜，研究基于其堆垛异质结构的波长可调节、高量子效率光探测器。研究内容包括：1)以MoS2和WSe2为代表，研究高结晶质量和柔性基底兼容的单层MoS2和WSe2薄膜的PECVD制备工艺，阐明原子层薄膜的生长规律与机制。2)结合结构表征、光谱分析、及基于场效应晶体管的载流子电输运测试，评价所制备的原子层薄膜质量。3)构筑单层MoS2、WSe2及其堆垛异质结构光探测器，研究其光探测性能及光响应机理。本研究旨在探索制备大面积、高质量原子层TMDC薄膜的新方法，探寻原子层二维TMDC半导体薄膜及其异质结构光响应的新性能，为二维TMDC半导体材料及其光电器件应用基础研究提供科学参考。

单层过渡金属硫化物(TMDC)半导体因具有直接带隙和独特光与物质相互作用效应，成为新型电子与光电子材料研究的热点，而大面积均匀、高质量单层薄膜的可控制备是实现其规模化光电器件的关键。本项目主要研究二维TMDC薄膜的大面积气相沉积制备及其原型光电探测器件。主要研究结果包括，1.选择低压沉积化学气相沉积（LPCVD）成功制备了晶圆尺度单层WS2薄膜，表面气体吸附强烈影响其载流子输运性质与光电响应特性；2. 以MoS2薄膜为例，发展了一种基于衬底移动的常压化学气相沉积（APCVD）层数可控的TMDC制备方法；3. 发展了一种大面积自动聚焦拉曼成像技术，为提高二维材料表征效率提供了有益参考；4. 在对所制备的两种TMDC薄膜进行系统性结构表征的基础上，制备了WS2/Si PN结型齐纳隧穿型光电二极管探测器，器件响应度超过商业化硅基二极管探测器，还制备了WS2-ZnO，WS2-graphene等高响应度光电导型探测器，进而深入研究了其光电响应特性及其较强光电转换的物理机制。本项目研究结果为其它二维过渡金属硫族化合物的制备、基本性质和原型器件研究提供科学指导，为二维晶体材料基器件规模化集成奠定基础。