Controlling the electronic and optical properties of two-dimensional crystal heterostructures

二维（2D）晶体如石墨烯或过渡金属二硫属化物（TMD）由于其独特的物理性质而成为用于开发未来器件的有前途的材料。到目前为止，广泛的调查已经完成了对个人，原子薄，2D层。最近，报道了以垂直堆叠的形式组合不同的2D结构的实验工作，货车德瓦尔斯键合异质结构（HS），并且展示了原理验证器件，例如晶体管、二极管、光电二极管、太阳能电池。异质结构是由单个2D结构之间的相互作用形成的，并且器件的潜在功能探索了这些层间相互作用。到目前为止，只有很少的了解如何这样的二维层相互作用，什么属性被修改的相互作用，以及如何才能获得精确的控制这些属性。通过这个项目，我们希望联合收割机结合实验和理论方法来研究二维HS的电子，光学，结构和振动特性。我们将探讨各种不同的2D HS通过考虑多个组合内的一组诱导TMD。主要目标是（1）开发制造方法，允许控制生产具有明确定义的可再现特性的高质量2D HS，并表征其电子和光学特性，（2）开发基于TMD的2D-HS的理论研究平台，（3）了解HS的电子结构和光学性质如何与单个单层的性质相关，以及HS中出现了哪些新效应，以及（4）通过对材料组合、层间取向差角和层数的明智选择来控制HS的电子结构和光学性质

Two-dimensional (2D) crystals such as graphene or transition metal dichalcogenides (TMD) are promising materials for the development of future devices because of their unique physical properties. So far, extensive investigations have been done on the individual, atomically thin, 2D layers. Recently, experimental works on the combination of different 2D structures in form of vertically stacked, van der Waals bonded heterostructures (HS) are reported and proof-of-principle devices, such as transistors, diodes, photodiodes, solar cells, were demonstrated. Heterostructures are formed by the interaction between individual 2D structures and the potential function of a device explores these interlayer interactions. So far there is only little understanding about how such 2D layers interact, what properties are modified by the interactions and how one can obtain precise control over these properties. With this proposed project we want to combine experimental and theoretical methods to investigate the electronic, optical, structural and vibrational properties of 2D HS. We will explore a variety of different 2D HS by considering multiple combinations within the set of semiconducing TMDs. The central objectives are to (1) develop fabrication methods that allow for the controlled production of high-quality, 2D HS with well-defined, reproducible properties and characterize their electronic and optical properties, (2) develop a platform for the theoretical study of TMD-based 2D-HS, (3) understand how the electronic structure and optical properties of the HS are related to the properties of the individual monolayers and what new effects arise in HS, and (4) control the electronic structure and optical properties of HS using an informed choice of material combination, interlayer misorientation angle and number of layers