Roadmap to perfect contacts in 2D electronics

Two-dimensional (2D) materials, including graphene and transition metal dichalcogenides (TMDs), hold promise for advancing ultra-scaled transistors, flexible devices, and high-performance optoelectronics. However, the contact interface between 2D materials and metal electrodes remains a significant challenge. A recent review by researchers at South China Normal University and the International Quantum Academy in Shenzhen, published in Nano Research on May 15, 2026, delves into the complexities of this interface, particularly focusing on the Schottky barrier.

Xu Zhou, a professor at South China Normal University, emphasized the dual role of the contact interface in devices. In transistors, the Schottky barrier can limit performance, while in photodetectors or sensors, it becomes a critical component. The review discusses how the atomic thinness of 2D materials renders traditional contact engineering methods, like heavy doping, ineffective. Instead, the authors propose innovative strategies such as van der Waals integration, interfacial doping, edge contacts, and the use of semimetals like bismuth and antimony to achieve ultralow-resistance Ohmic contacts.

Co-corresponding author Xiaozhi Xu highlighted the issue of Fermi-level pinning (FLP), a persistent problem in 2D electronics caused by defects, chemical bonding, or strain at the interface. The review suggests that controlling these factors through cleaner fabrication or novel contact geometries can depin the Fermi level and restore tunability. Additionally, the use of Schottky contacts in devices like photodetectors and gas sensors is explored, where the built-in electric field aids in efficient charge separation and signal modulation.

The review advocates for a shift from empirical contact design to theory-informed engineering, supported by advanced characterization and scalable fabrication techniques. Jing Liang, co-corresponding author, stressed the need for standardized metrology and integration methods compatible with existing semiconductor manufacturing to facilitate the transition of 2D materials from laboratory research to industrial applications.

Supported by various Chinese research foundations, this comprehensive review serves as a foundational reference for researchers in the field of 2D electronics and optoelectronics. It underscores the importance of multidisciplinary collaboration in pushing the boundaries of these technologies.