Fundamental and Photodetector Application of Van Der Waals Schottky Junctions

Two-dimensional (2D) materials with unique band structures have shown great potential for modern electronics and optoelectronics. The junction composed of metals and 2D van der Waals (vdW) materials, which is characterized by the Schottky barrier, is crucial to the device performance as well as functionality. However, it usually suffers from uncontrollable Schottky barrier due to the strong Fermi level pinning (FLP) effect, which hinders the further optimization of devices. In this review, we summarized the origin of FLP by introducing different models. Several Fermi level depinning strategies were then discussed to enable the tuning of Schottky barrier, which can be used for the precise design and modulation of vdW Schottky diode. We further reviewed the progress of the state-of-the-art photodetectors based on vdW Schottky junction in terms of different configurations and working principles. The strategies for improving the performance of vdW Schottky junction-based photodetector was also presented. Finally, we provided a summary and outlook for the development of vdW Schottky junction and photodetectors.