Gate-Tunable PdSe2/WSe2 van der Waals Heterostructures for Ultrahigh Light On–Off Ratio Polarization-Sensitive Photodetection

• • Achieved ultrahigh light on-off ratio exceeding 10^6, enabling high-contrast detection in low-light conditions, critical for sensitive imaging and communication systems. • • Demonstrated gate-tunable photoresponse with responsivity up to 1.2 A/W and specific detectivity of 10^12 Jones, allowing dynamic sensitivity adjustment for varying illumination. • • Exhibited polarization-sensitive detection with a linear dichroism ratio of 2.1 at 532 nm, enabling discrimination of light polarization for applications in ellipsometry and secure communications. • • Self-powered operation with fast response times (rise/fall < 100 μs) and broad spectral range (400-1000 nm), reducing power consumption and enabling high-speed, broadband photodetection.