Researchers from Peking University, Beijing Graphene Institute, University of Chinese Academy of Sciences and the University of Manchester have developed a new method to integrate 2D semiconductors with dielectric materials. Their approach involves the epitaxial growth of an ultra-thin dielectric film on a graphene-covered copper surface, which subsequently enables its transfer onto various substrates with minimal defects.
The new method addresses the challenges in integrating 2D materials(like graphene) into microelectronic devices. As conventional transfer methods that use polymer supports often introduce chemical contamination, various mechanical issues and interfacial defects, the team set out to develop a wafer-scale process that overcomes these issues, by preserving graphene's intrinsic properties and ensuring a clean, well-controlled interface during transfer and encapsulation.
To demonstrate their process, the scientists first synthesized a single-crystal dielectric, namely antimony oxide (Sb2O3). They then deposited this dielectric on graphene that was grown on a copper substrate. The copper was pre-treated with a water-ethanol mixture to form a thin oxide layer, reducing the adhesion between graphene and copper. The dielectric layer not only supports the transfer but also acts as the encapsulating layer, thereby protecting it from contamination and mechanical damage.
Notably, the researchers showed that the process enabled the reliable transfer of a 4-inch graphene wafer onto target substrates with minimal defects. In the future, this could open new possibilities for the development of new electronics that combine 2D semiconductors with dielectric materials. This recent work has notable practical implications, as the method developed could enable the scalable fabrication of various highly performing and low-power microelectronics and optoelectronics based on 2D materials.
Looking ahead, the researchers plan to build on their approach, while also trying to extend it to the 3D integration of 2D materials in real devices.
