GATES

The purpose of the proposal of the European collaborative project GATES, of which the Greek project is a part, is to experimentally achieve (at TRL 4 level) the creation of a new membrane based on CVD graphene, which will be highly selective in terms of gas separation.

The main idea of the proposal relies on technologically innovative concepts regarding the creation of pores. The devices to be developed will be compatible with CMOS technology to ensure their manufacturability. The basic experimental concept for creating the membrane device avoids one of the main risky steps in graphene technology — the transfer of a monolayer after its growth. The transfer stage is industrially challenging, as it results in significant macroscopic defects that severely limit the performance of the membrane.

The ambition of the GATES proposal is to develop and demonstrate a graphene membrane fabrication technology that does not require graphene transfer and is compatible with CMOS technology. In the final device, two parts will be stacked to enhance selectivity by introducing curvature. To achieve very high selectivity, nanometer-sized pores must be created. The initial pyridinic or pyrrolic vacancies in the graphene monolayer will be generated through nitrogen doping using various plasma technologies.

In both cases, the statistics of pore sizes and shapes will be studied using TEM microscopy, carried out by teams participating in the project consortium. This study will provide the input parameters for the modeling of membrane performance. Additionally, complementary characterization techniques such as Raman and XPS spectroscopy will be used to gain a deeper understanding of the membrane properties.

Within the project, the permeability properties of graphene—pure, with various types of defects, with nitrogen doping, and with the addition of different functional groups—will be investigated using theoretical models, which constitutes the main research activity of the Greek subproject implemented at NHRF (National Hellenic Research Foundation). At a later stage, the permeability of bilayer graphene will also be studied theoretically.

The theoretical modeling will support the experimental research and will be used to determine the optimal structure for the best combination of permeability and selectivity. Another objective of the GATES proposal is to assess the role of pores at grain boundaries through simulations of the permeability of local configurations, such as pentagon/heptagon structures.

The development of such a graphene membrane and its application in leak detection will provide a significant innovative product for technological applications, offering an extremely portable and integrated device with a very short response time.