Ultrabroadband Photosensitivity and Frequency-Mixing in Anisotropic Weyl Semimetal NbNiTe2

Broadband anisotropic photodetectors show great promise for polarization-sensitive imaging and multispectral optoelectronic systems yet face critical challenges in material anisotropy modulation and broadband sensitivity. Weyl semimetals exhibit giant optical anisotropy and tunable heterojunction band alignment, enabling high-performance anisotropic photodetection. Herein, ultrabroadband PDs based on the NbNiTe2 (niobium nickel telluride), enabled by antenna integration and heterostructure engineering, achieve high sensitivity from visible to Terahertz (THz). Leveraging its topological quantum material properties and antenna integration, NbNiTe2-based PDs demonstrate high responsivity of 5.86 A/W and fast response time of 0.83 μs in the THz regime. Combined with the nonlinear property of the NbNiTe2-based PDs, a heterodyne experiment is developed, demonstrating their potential for multifrequency THz signal detection and applicability in complex signal processing. The NbNiTe2/MoS2 heterostructure engineered PDs exhibit a remarkably specific detectivity (D*) ranging from 1.37 × 1011 to 4.08 × 1011 cm·Hz0.5·W–1 and broad spectral response covering visible to near-infrared (NIR) wavelengths. Meanwhile, these NbNiTe2-based PDs exhibit significant anisotropic properties, a high electrical conductivity anisotropy ratio of 16.9 and an ultrahigh anisotropy ratio of 5.74. These findings can provide a viable pathway for next-generation room-temperature broadband PDs with high sensitivity and anisotropy.