Flexible and High-Performance All-2D Photodetector for Wearable Devices

Emerging novel applications at the forefront of innovation horizon raise new requirements including good flexibility and unprecedented properties for the photoelectronic industry. On account of diversity in transport and photoelectric properties, 2D layered materials have proven as competent building blocks toward next-generation photodetectors. Herein, an all-2D Bi₂ Te₃ -SnS-Bi₂ Te₃ photodetector is fabricated with pulsed-laser deposition. It is sensitive to broadband wavelength from ultraviolet (370 nm) to near-infrared (808 nm). In addition, it exhibits great durability to bend, with intact photoresponse after 100 bend cycles. Upon 370 nm illumination, it achieves a high responsivity of 115 A W^-1 , a large external quantum efficiency of 3.9 × 10⁴ %, and a superior detectivity of 4.1 × 10¹¹ Jones. They are among the best figures-of-merit of state-of-the-art 2D photodetectors. The synergistic effect of SnS's strong light-matter interaction, efficient carrier separation of Bi₂ Te₃ -SnS interface, expedite carrier injection across Bi₂ Te₃ -SnS interface, and excellent carrier collection of Bi₂ Te₃ topological insulator electrodes accounts for the superior photodetection properties. In summary, this work depicts a facile all-in-one fabrication strategy toward a Bi₂ Te₃ -SnS-Bi₂ Te₃ photodetector. More importantly, it reveals a novel all-2D concept for construction of flexible, broadband, and high-performance photoelectronic devices by integrating 2D layered metallic electrodes and 2D layered semiconducting channels.