Recent developments in the photodetector applications of Schottky diodes based on 2D materials

In recent years, 2D layered materials have emerged as potential candidates in the opto-electronic field due to their intriguing optical, electrical and mechanical properties. Photodetectors based on 2D materials have been reported to exhibit excellent photodetection capability due to their tunable bandgap and ability to detect broadband spectrum ranging from UV to NIR. Schottky junction-based detectors are highly sensitive and fast responsive compared to other heterojunction devices. Schottky contacted devices are fabricated by constructing a heterojunction of a semiconductor with a metal or a metal-like material. In the case of 2D material-based photodetectors, either the semiconductor or the metal belongs to the 2D family. The detection properties of Schottky contacted devices are mainly dependent on the junction properties such as the barrier height. The photodetection performance of detectors with 2D materials is observed to be superior and further it can be enhanced by tuning the properties through various strategies. Herein, the basic concepts, detection mechanism and evaluation parameters of Schottky junction-based photodetectors and the recent developments in Schottky junction-based photodetectors achieved using various 2D materials in the past five years are reviewed. Emerging strategies to enhance the performance by adjusting the Schottky barrier height are elaborated. Finally, the summary and future prospects are provided.