Ultra-Broadband and Polarization-Sensitive TaPdTe₅-Based Photodetectors from Visible to Terahertz Wavelength

Polarization-sensitive photodetectors operating from ultraviolet to terahertz (THz) can acquire more multidimensional information compared to conventional PDs, making them ideal for complex applications like military and environmental monitoring. However, most topology-based photodetectors are based on two-dimensional (2D) or three-dimensional (3D) systems, and quasi-one-dimensional (quasi-1D) topological crystals combining polarization sensitivity with ultrabroadband detection remain scarce. Here, we demonstrate a quasi-1D topological semimetal, TaPdTe₅, for high-performance photodetection spanning visible to THz bands. Topological TaPdTe₅ not only possesses an extremely rare and highly in-plane anisotropic structure, but also the TaPdTe₅-based photodetector exhibits excellent comprehensive photoelectric performance (extremely low noise-equivalent power of 0.0174 pW·Hz^-1/2 at 0.0896 THz, ultrafast response times of 47.8 μs at 808 nm and 1.3 μs at 0.0896 THz) and environmental stability. Owing to its low-symmetry crystal structure and dipole antenna effects, the TaPdTe₅-based photodetector shows polarization-dependent response across visible, infrared, and THz wavelengths, achieving an extremely high extinction ratio of 128 at 25.2 GHz. Furthermore, the TaPdTe₅ photodetector is successfully deployed for high-resolution, fast THz imaging applications at room temperature. Our findings highlight TaPdTe₅ as a promising quasi-1D topological semimetal for next-generation multifunctional ultrabroadband optoelectronic devices.