Devices based on two-dimensional (2D) semiconductors are now moving from singular observations in the laboratory to an integrated platform for high performance electronics. To ensure a smooth technology transition, it is critical to address the challenges that affect device yield, performance and reproducibility. One such challenge is achieving clean electrical contacts. The deposition of defect-free van der Waals (vdW) metallic contacts on atomically thin 2D semiconductors is a promising and scalable approach.[1] Here, we discuss the unique growth morphology of vdW metal contacts on 2D semiconductors, which results in uniform thin films with large grain size. [2] However, the applications of vdW contacts are not limited to electronics. We observe that the vdW gap between metals and 2D semiconductors can promote strong plasmonic coupling, leading to improved performance of optoelectronic devices. Finally, we discuss how ferromagnetic vdW contacts can enable robust room temperature spin injection in graphene without the need for the dielectric tunnel barriers used in state-of-the-art lateral spin valves, enabling reliable and scalable spintronic devices.
[1] Wang, Yan, and Manish Chhowalla. "Making clean electrical contacts on 2D transition metal dichalcogenides." Nature Reviews Physics 4.2 (2022): 101-112.
[2] Ghani, Maheera Abdul, et al. "Metal Films on Two-Dimensional Materials: van der Waals Contacts and Raman Enhancement." ACS Applied Materials & Interfaces (2024).