Nanometer-scale chemical modification of 2D materials

In the project "Nanometer-scale chemical modification of 2D materials", we study how to design new two dimensional (2D) materials with specific properties. Designing and developing new materials is an important aspect of materials science. Materials properties can be modified by e.g. altering the original atomic structure of the material. 2D nanomaterials that consist of a single or a few layers of atoms are especially interesting regarding materials design due to their 2D nature. By changing the atomic structure of a 2D material even by a single atom, the properties of the material can change radically. These new materials could then fit better the needs of a new generation of applications with superior performance and capabilities. The applications range form e.g sensors to nanoelectronics and filters.

The methods used in this study include electron microscopy and computational simulations. Electron microscopy allows us to see the materials structure down to individual atoms. By using the unique electron microscope set up at the University of Vienna, we will introduce gas molecules onto the sample surface. These molecules then interact with the electron beam that is used to image the sample leading to etching of the sample surface. Conventionally etching is avoided while using electron microscopes, because it introduces uncontrolled and undesired effects in the sample. Our aim is to control the etching and use it in advantage to engineer 2D materials. We will control the etching by introducing specific alterations in the atomic lattice. This will allow us to controllably create nanoscale features such as cuts in predetermined directions leading to formation of nanowires and nanoribbons, and pores of different size. These features can then be used in varying new nanoscale applications such as sensors and filters.

To fully understand the mechanisms involved in the process we will use atomistic simulations to model the system further. We will create a new neural network potential to describe the interactions of gas molecules on 2D surface with full chemical description of the system. At present this can not be achieved with the existing methods at the required scale. This part of the project will result in one of the first potentials to model chemical reactions in large scale systems with quantum precision. Our work will help develop and design new 2D materials with controlled properties using a novel approach for a new generation of nanoscale applications.