High Performance Self-Driven Photodetectors Based on MoS₂ Schottky Barrier Diode

Practical application of two-dimensional transition metal dichalcogenides (2D TMDCs) involves creating a p-n diode and a Schottky diode. Unlike p-n diodes, the research of 2D material-based Schottky diodes especially in the application field of photodetectors is lacking. Here, a Schottky diode is fabricated by depositing Pt and Ni on the MoS2 to form Schottky and ohmic contacts, respectively. The MoS2 Schottky diode exhibits a rectification ratio of 2.36 x 10(3) and an ideality factor of 1.12. The electrical characteristics of Ni-MoS2-Ni and Pt-MoS2-Pt field effect transistors are systematically compared. The Schottky barrier height is estimated to be 94.2 meV by using the thermionic emission theory. The Schottky diode device can exhibit excellent self-powered photodetection performance in the visible to near-infrared region (447-940 nm) due to the strong built-in electric field originating from the Schottky barrier at the MoS2/Pt interface. The maximum detectivity reaches 2.09 x 10(12) Jones with a response time of 52.6 ms under 940 nm laser illumination. Furthermore, the photodetection performance of such a Schottky diode can be further improved by NH3 plasma doping treatment. This work provides not only a simple approach to construct a 2D materials-based Schottky diode photodetector but also a post treatment technique to further improve the device performance.