Pulsed thermal deposition of transition metal dichalcogenides

过渡金属二硫族化合物（TMDC）是二维范德华材料类中最有趣的成员。就基本的电子特性和导电性而言，TMDCs跨越了从金属（V族TMDCs）到半导体（VI族TMDCs）的范围。半导体TMDCs的光学响应由库仑束缚的中性和带电激子（trions）控制到室温。当TMDCs减薄到单层时，它们负责高光-物质相互作用截面和光致发光收率。这些有利的光学性质与相当高的载流子迁移率相辅相成，高达几百平方厘米每伏特秒，以及p和n掺杂的可行性。为了为TMDCs在器件中的实际应用铺平道路，需要一种制造方法，该方法允许具有确定成分的合金的可重复性制备，以及具有清洁和原子锋利界面的多层交替材料的连续生长。该项目的总体目标是为结构完美的晶圆级TMDC垂直异质结构获得可靠的基于知识的制造路线，并揭示其实现具有所需光电功能的复杂异质结构的可行性。这包括带隙工程和单层可控掺杂TMDCs，以及多层结构中层厚的精确控制。要实现这些目标，需要详细了解TMDCs在不同基质上的成核机制和生长动力学，以及对新型合成材料的基本物理性质的全面表征。

Transition metal dichalcogenides (TMDC) are most intriguing members of the two-dimensional van-der-Waals material class. In terms of fundamental electronic properties and conductivity, TMDCs span the range from metal (group V TMDCs) to semiconductor (group VI TMDCs). The optical response of the semiconducting TMDCs is governed up to room temperature by Coulombically bound neutral and charged excitons (trions). They are responsible for the high light-matter interaction cross section and photoluminescence yield when TMDCs are thinned to the monolayer regime. These favorable optical properties are complemented by fairly high charge carrier mobility, up to a few hundred square centimeters per volt second, as well as the feasibility of p- and n-doping. To pave the way for practical applications of TMDCs in devices, a fabrication method is required which allows reproducible preparation of alloys with defined composition as well as continuous growth of multiple layers of alternating materials with clean and atomically sharp interfaces. The overarching goal of the project is to attain a reliable knowledge-based fabrication route for structurally perfect wafer-scale TMDC vertical heterostructures, and to unravel its feasibility to realize complex heterostructures that enable desired optoelectronic functions. This includes band gap engineering and controllable doping of TMDCs at the monolayer level and precise control of the layer thickness in multilayer structures. Achieving these goals requires detailed understanding of the nucleation mechanisms and growth kinetics of TMDCs on different substrates, as well as a comprehensive characterization of the fundamental physical properties of the novel synthetized materials.