Van Der Waals Metal Contacts for Electronic and Optoelectronic Devices

For the fabrication of thin-film electronics, conventional physical vapor deposition (PVD) processes have been widely used to form metal contacts on various thin films. However, the PVD process, involving thermally activated high-energy metal atoms, damages the underlying thin films, severely deteriorating the performance and stability of the device. The van der Waals (vdW) metal-contact approach has recently emerged to avoid this issue. By transferring predeposited metal contacts using vdW interactions, atomically sharp and electronically clean heterointerfaces can be formed without generating unintended defects. In this article, we review the fundamentals, processes, and various applications of the vdW metal-integration approach. The classical theory of vdW interactions is first reviewed, followed by the introduction of various approaches for constructing vdW metal contacts on thin films. Subsequently, the influence of contact configuration on the performance of various applications is summarized. Finally, the remaining challenges and prospects are discussed for the practical usage and versatile application of vdW metal contacts for next-generation electronic devices.