Functionalization of ultrathin MoS_2 by defect engineering

该项目的总体目标是开发通过离子诱导电子激发使2D材料功能化的策略。通过电子激发的能量沉积引起的缺陷，明显不同于那些由传统的（即单电荷keV）离子束的类型，大小和效率方面创建的。离子诱导的缺陷将例如通过前体气体或分子的吸附而进一步改性。我们的目标是通过对单层MoS_2的系统实验来识别和量化相关的缺陷产生机制-作为过渡金属二硫属化物材料类的代表-结合理论建模。这种方法为有效的缺陷工程策略奠定了基础，即它将使我们能够预测和选择最佳参数，用于在给定样品中控制制造特定缺陷结构。特别是，我们将把我们的注意力集中在单层MoS_2的功能化三个不同的应用程序，其中每一个是基于一个特定的缺陷类型。基于我们的初步工作，这些是：具有小尺寸分布的纳米孔适合于水脱盐或DNA测序，脱硫MoS_2纳米结构适合于析氢反应（HER），和缺陷工程MoS_2场效应晶体管，可用作光电开关。

The overall goal of this project is to develop strategies to functionalize 2D materials by means of ion-induced electronic excitations. The energy deposition via electronic excitations gives rise to defects which clearly differ from those created by conventional (i.e. singly charged keV) ion beams with respect to type, size and effciency. The ion-induced defects will be further modified e.g. by the adsorption of precursor gases or molecules. Our objective is to identify and quantify the relevant defect creation mechanisms by systematic experiments on single layer MoS_2 - as a representative of the material class of transition metal dichalcogenides - in combination with theoretical modelling. This approach builds the basis for effcient defect engineering strategies, i.e. it will enable us to predict and choose the optimum parameters for the controlled fabrication of a certain defect structure in a given sample. In particular, we will focus our attention on the functionalization of single layer MoS_2 for three different applications, each of which is based on a specific defect type. Based on our preliminary work these are: nanosized pores with a small size distribution suitable for water desalination or DNA sequencing, desulfurized MoS_2 nanostructures suitable for the hydrogen evolution reaction (HER), and defect engineered MoS_2 field effect transistors which may be used as optoelectronic switches.