Self-Powered ZnO@PdTe₂/Si Heterojunction Photodetector with an Ultrafast Response for Color Imaging and Optical...

Broadband photodetectors have attracted much attention due to their multispectral response properties and show great potential in the fields of optical sensing, multispectral imaging, and optical communications. Palladium telluride (PdTe₂) is highly competitive in broadband detection due to its tunable bandgap and nonlinear optical properties. However, the low response speed hinders further improvement in the performance of PdTe₂-based broadband photodetectors. In this work, we present island-type ZnO@PdTe₂ composites on Si as a heterojunction photodetector exhibiting highly sensitive photodetection capabilities in a wide band from the solar-blind region (254 nm) to the short-infrared (1.55 μm). Due to the island-type morphology of the ZnO@PdTe₂ composites effectively enhancing light absorption and the ZnO@PdTe₂/Si stacks forming a type-II heterojunction accelerating carrier separation, the devices have an ultrafast response (1.58/1.34 μs), a detectivity of up to 1.56 × 10¹³ Jones, and a sensitivity of up to 10⁷ cm²/W. A triple-channel color imaging system and a dual-channel data transmission system were developed based on the excellent and stable performance of the device. This study demonstrates the great potential of ZnO@PdTe₂/Si vertical heterojunction photodetectors for high-speed, wide-band, multiscenario optical communication.