Anisotropic Broadband Photo Response of Layered Type-II Weyl semimetals

T_d-MoTe₂ and TaIrTe₄, two-dimensional layered Type-II Weyl semimetal, are expected to share several unique advantages with Dirac semimetals for photodetection. The extremely high mobility and the chiral Fermions near the Weyl node lead to several advantages over traditional semiconductor-based photodetectors. Here, we report the realization of broadband self-powered photodetectors based on T_d-MoTe₂ and TaIrTe₄. Broadband responses from visible to mid-infrared are experimentally tested. The PC generation mechanisms are investigated and it is found that PTE effect plays critical role in PC generation. Furthermore, we found that the anisotropy is wavelength dependent, and the degree of anisotropy increases as the excitation wavelength gets closer to the Weyl nodes which can be used for polarization-sensitive photo detection. Thus T_d-MoTe₂ and TaIrTe₄ provide a new class of material platform for high performance photodetection applications