PdSe 2 /MoSe 2 vertical heterojunction for self-powered photodetector with high performance

Van der Waals’ two-dimensional (2D) material heterostructure engineering offers an effective strategy for the design of multifunctional and high-performance optoelectronic devices. However, 2D heterostructure photodetectors with a photoconductive effect tend to suffer from high driving source-drain voltages and significant dark noise currents. Herein, a self-powered photodetector with high performance was fabricated based on vertically stacked graphene/MoSe 2 /PdSe 2 /graphene heterojunctions through a dry transfer method. The fabricated device displays current rectification characteristics in darkness (on/off ratio > 10 3 ) and superior photovoltaic behaviors under illumination. In addition, benefitting from the strong built-in field, the Gr/PdSe 2 /MoSe 2 /Gr heterojunction photodetector is able to respond to a broad spectrum from visible to near-infrared (NIR) with a remarkable responsivity of 651 mA·W −1 , a high specific detectivity of 5.29 × 10 11 Jones and a fast response speed of 41.7/62.5 µs. Moreover, an enhanced responsivity of 1.16 A·W −1 has been obtained by a reverse voltage (−1 V) and further evaluation on image recognition has also demonstrated the great application potential of the Gr/MoSe 2 /PdSe 2 /Gr heterojunction photodetector. The findings are expected to bring new opportunities for the development of highly sensitive, high-speed and energy-efficient photodetectors for comprehensive applications.