Low energy ion irradiation of 2D-materials

这项后续计划的研究目标是发现和研究负载型2D材料中的离子辐照诱导现象。一方面，我们将完成已经在第一个项目阶段开始的研究，从同时发展的新观点调查主题，补充现有的数据集，以及通过公布结果，以推进和刺激进一步的研究。另一方面，我们将在第一个资助期出现的重大发现和成就的基础上，探索科学新领域I.纳米网格：在人们对2D材料作为膜的应用兴趣日益高涨的推动下，我们将开发独特的基于莫尔的离子束方法来实现这类膜。我们将完善和发展我们在石墨烯和六方氮化硼中以Ir(111)或Pt(111)为载体的空位团簇纳米颗粒的工作。在根本方面，我们将进行额外的实验、计算和模拟，以了解所发现的神奇空位团簇尺寸的形成以及导致双峰空位团簇尺寸分布的机制。在实际应用方面，我们打算在规律性、均匀和可调节的大小方面优化纳米网格的形成配方，以及不存在会恶化作为滤膜的应用的较大空位岛。此外，我们将建立这些纳米网格层的转移，并用透射电子显微镜对其进行表征。过渡金属二硫化物中的相变：随着过渡金属二硫化物单层作为准独立层在Ir(111)上的石墨烯上的存在，研究离子束如何在这些材料中诱导相变成为可能。作为一个范例，我们将完整地描述可逆的离子束诱导的MoS_2从晶态到非晶态的转变，包括扫描隧道光谱和显微镜、光致发光以及拉曼光谱。我们将进一步研究如何使用离子束在这些层中诱导其他结构相变。高压化学和同位素分离：最后，我们将利用我们的发现，在GPA压力下，注入的气体被困在Ir(111)上石墨烯或六方氮化硼单层下的水泡中，即使这些层是高度缺陷的。这一发现意味着，如果水泡中可以充满活性气体，就有可能产生高压化学。此外，由于我们发现与温度相关的气体保留也取决于气体的种类，我们将探索这种效应是否也可以用于同位素分离，例如氢和氢的分离。

The objective of the research within this follow-up proposal is to discover and investigate ion irradiation induced phenomena in supported 2D-materials. On the one hand, we will complete research that started already in the first project phase by investigating topics from new viewpoints that developed meanwhile, by supplementing existing data sets, as well as through publication of results in order to advance and stimulate further research. On the other hand, we will build on significant findings and achievements that emerged during the first funding period to explore scientific new ground.I. Nanomesh: Driven by the rising interest in application of 2D-materials as membranes, we will exploit the unique moiré-based ion beam approach for the realization of such membranes. We will refine and develop our work on the vacancy cluster nanomeshes in graphene and hexagonal boron nitride supported by Ir(111) or Pt(111). On the fundamental side we will conduct additional experiments, calculations and modelling to understand the formation of the magic vacancy cluster sizes discovered and the mechanism giving rise to a bimodal vacancy cluster size distribution. On the practical side, we intend to optimize the recipes for nanomesh formation in terms of regularity, uniform and tunable size, as well as the absence of larger vacancy islands that would deteriorate an application as filtering membrane. Moreover, we will establish the transfer of these nanomesh layers and characterize them by transmission electron microscopy. II. Phase transitions in transition metal disulfides: With the availability of transition metal disulfide monolayers as quasi-freestanding layers on graphene on Ir(111) it becomes possible to investigate how ion beams can induce phase transitions in these materials. As a paradigm, we will fully characterize the reversible ion beam induced crystalline-to-amorphous transition of MoS2 including scanning tunneling spectroscopy and microscopy, photoluminescence, as well as Raman spectroscopy. We will furthermore investigate how ion beams can be used to induce other structural phase transitions in such layers. III. High pressure chemistry and isotope separation: Finally, we will utilize our finding that implanted gases are trapped in blisters underneath graphene or hexagonal boron nitride monolayers on Ir(111) at GPa pressures, even when these layers are highly defective. This finding implies a potential for high pressure chemistry, if blisters can be filled with reactive gases. Moreover, as we found that the temperature dependent gas retention also depends on the gas species, we will explore whether this effect may also be used for isotope separation, e.g. for the separation of hydrogen and deuterium.