Triple-Enhanced Absorption Anisotropy in Arrayed Core-Shell Nanowire Design.

One-dimensional semiconductor nanowires (NWs) are natural polarization photodetectors, thanks to their optical absorption anisotropy and efficient electrical transport channels. However, ultrathin NWs beyond practical fabrication capabilities are often required to achieve the desired polarization sensitivity. Here, we demonstrate a configuration of planar arrayed core-shell NW architectures with substantially enhanced absorption dichroism for linearly polarized light. The high polarization ratio originates from synergistic effect of three rational designs: a NW core consisting of indirect-bandgap semiconductor as light-trapping cavity, a thin shell of photosensitive material as light absorber, and arrayed photonic structure for optical interference. By employing all-inorganic halide perovskites, these NW arrays exhibit a dichroic ratio up to 110.5 without the need for ultrathin NWs. The core-shell NW architecture is experimentally feasible and offers insights into design of high-sensitivity polarization photodetectors using optical resonance.