Symmetry‐Reduction Enhanced Polarization‐Sensitive Photodetection in Core–Shell SbI 3 /Sb 2 O 3 van der Waals Heterostructure

Structural symmetry is a simple way to quantify the anisotropic properties of materials toward unique device applications including anisotropic transportation and polarization‐sensitive photodetection. The enhancement of anisotropy can be achieved by artificial symmetry‐reduction design. A core–shell SbI 3 /Sb 2 O 3 nanowire, a heterostructure bonded by van der Waals forces, is introduced as an example of enhancing the performance of polarization‐sensitive photodetectors via symmetry reduction. The structural, vibrational, and optical anisotropies of such core–shell nanostructures are systematically investigated. It is found that the anisotropic absorbance of a core–shell nanowire is obviously higher than that of two single compounds from both theoretical and experimental investigations. Anisotropic photocurrents of the polarization‐sensitive photodetectors based on these core–shell SbI 3 /Sb 2 O 3 van der Waals nanowires are measured ranging from ultraviolet (UV) to visible light (360–532 nm). Compared with other van der Waals 1D materials, low anisotropy ratio ( I max / I min ) is measured based on SbI 3 but a device based on this core–shell nanowire possesses a relatively high anisotropy ratio of ≈3.14 under 450 nm polarized light. This work shows that the low‐symmetrical core–shell van der Waals heterostructure has large potential to be applied in wide range polarization‐sensitive photodetectors.