The new method revolutionizes the production of low-cost van der Waals nanosheets

(Nanowerk Highlights) A research team from the Material Science Factory at the Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) has developed a breakthrough method for high-yield mechanical exfoliation, enabling the low-cost production of van der Waals nanosheets.

The technique, presented in their most recent publication at Little Method (“High Throughput Mechanical Peeling for Low Cost Production of Nano van der Waals Sheets”), offers a significant advancement in manufacturing low-cost devices that can be scalable while maintaining excellent performance. Composite image showing a roll-to-roll-like arrangement to perform high-throughput mechanical exfoliation, an example of a film composed by exfoliated flakes deposited on SiO2/ Si chip and field effect transistor devices are made from one of these films. (Image courtesy of the researchers)

Mechanical exfoliation, the process of isolating a two-dimensional (2D) material from its bulk material, has long been recognized for its ability to produce materials of exceptional quality. However, the lack of control over thickness and lateral sizes, as well as the difficulty of improving the process, have created significant challenges. Previous attempts to overcome this limitation required complicated transfer techniques or were not suitable for certain van der Waals materials.

In their study, the research team developed an automated, massively parallel exfoliating process using a roll-to-roll arrangement. This innovative approach allows for the production of high nanosheet density adhesive tapes, achieving a balance between large lateral size and excellent area scalability, while maintaining low costs. The video shows the process of exfoliating the van der Waals material. (Source from researchers)

The versatility of this production method extends to a wide range of van der Waals substrates and materials, making it a promising avenue for different combinations of 2D materials. By attaching these tapes to the surface of the acceptor and subjecting them to a gentle annealing process, most materials can be transferred effectively. The researchers were able to demonstrate the potential of this technique by manufacturing large numbers of flexible field-effect transistors and photodetectors.

“Our development of a high-yield mechanical exfoliation technique opens up exciting possibilities for the fabrication of low-cost devices,” said Dr. Andrés Castellanos-Gomez. “With this method, we have achieved a remarkable trade-off between cost, scalability and performance, paving the way for the widespread application of van der Waals nanosheets in a wide variety of fields.” Video showing the process of transferring peeled nanosheets from adhesive tape to any substrate. (Source from researchers)

The new method presents a significant improvement over existing approaches. While chemical vapor deposition (CVD) and liquid phase exfoliation (LPE) offer scalability and cost advantages, they often compromise control over thickness, lateral size, or electrical properties. In contrast, the newly developed technique combines a low cost, all-dry process even compatible with air-sensitive materials, excellent scalability and large lateral size, ensuring the production of 2D materials with superior electrical properties.

The breakthroughs achieved by the team at ICMM-CSIC have attracted much attention from the scientific community. It is poised to revolutionize applications requiring low-cost films composed of 2D materials such as smart coatings and biosensors. Provided by the Madrid Institute of Materials Science