过渡金属硫化物半导体-金属异质结的可控制备及性能研究

构建过渡金属硫化物（TMD）异质结是调控二维材料化学组成、光学与电学性质最有效的策略。半导体-金属异质结是现代电子学及光电子学器件的重要基本组成单元，半导体-金属的接触界面能够形成真正意义的欧姆接触，实现有效的载流子注入，制备高性能的电子及光电子器件。但是目前TMD半导体-金属异质结的可控制备仍存在巨大挑战。本项目在生长中引入碱金属卤化物，通过改变TMD材料的结合能，反应中间体的种类及生长模式，解决前驱体熔点较高，反应活动低，金属性材料生长困难，垂直及侧向异质结选择性低等问题，实现TMD半导体-金属异质结的可控制备，发展层状材料制备的普适策略。同时，以侧向异质结为基础制备边缘接触的场效应晶体管器件，验证半导体-金属异质结在提高器件性能中的作用。本项目的研究可以丰富TMD半导体-金属异质结的体系及制备方法，探索新的物理性能及应用，为其他二维材料的可控制备提供指导。

The construction of transition metal dichalcogenide (TMD) heterostructure is the most effective strategy to regulate the chemical composition, optical and electrical properties of two-dimensional materials. Semiconductor-metal heterostructure is the important basic component for modern electronics and optoelectronics, and it can also form real ohmic contact in the interface to benefit carrier injection and enhance the performance of electronic and optoelectronic transistors. However, it is still a great challenge to accurately construct and prepare semiconductor-metal heterostructures. This project aims to solve the problems of high melting point, low reaction of the precursors, the difficulty of metallic TMD materials growth and poor selectivity of vertical and in-plane heterostructures by adding alkali halide in the growth. By tuning the adhesion force (binding energy) and reaction intermediate growth mode, controllable synthesis of semiconductor-metal TMD heterostructures could be achieved with specific interface. The general strategy of preparing layered materials will be also developed. Further, filed-effect transistors with edge-contacts will be fabricated to verify the important effect of improving the device performance of the in-plane heterostructure. This research in the project would enrich the materials and preparation methods for TMD semiconductor-metal heterostructure, explore more physical properties and applications, and provide guidance for the preparation of other two dimensional materials.