Fibrous red phosphorus (RP) has triggered growing attention as an emerging quasi-one-dimensional (quasi-1D) van der Waals crystal recently. Unfortunately, it is difficult to achieve substrate growth of high-quality fibrous RP flakes due to their inherent quasi-1D structure, which impedes their fundamental property exploration and device integration. Herein, we demonstrate a bottom-up approach for the growth of fibrous RP flakes with (001)-preferred orientation via a chemical vapor transport (CVT) reaction in the P/Sn/I₂ system. The formation of fibrous RP flakes can be attributed to the synergistic effect of Sn-mediated P₄ partial pressure and the SnI₂ capping layer-directed growth. Moreover, we investigate the optical anisotropy of the as-grown flakes, demonstrating their potential application as micro phase retarders in polarization conversion. Our developed bottom-up approach lays the foundation for studying the anisotropy and device integration of fibrous red phosphorus, opening up possibilities for the two-dimensional growth of quasi-1D van der Waals materials.

纤维状红磷（RP）作为一种新兴的准一维（准一维）范德华晶体最近引起了越来越多的关注。不幸的是，由于其固有的准一维结构，难以实现高质量纤维状RP薄片的基底生长，这阻碍了其基本性能探索和设备集成。在此，我们展示了一种自下而上的方法，通过 P/Sn/I 2 系统中的化学气相传输 (CVT) 反应生长具有 (001) 优先取向的纤维 RP_薄片。纤维状RP薄片的形成可归因于Sn介导的P ₄分压和SnI ₂覆盖层定向生长的协同效应。此外，我们研究了生长薄片的光学各向异性，证明了它们作为偏振转换中微相位延迟器的潜在应用。我们开发的自下而上的方法为研究纤维状红磷的各向异性和器件集成奠定了基础，为准一维范德华材料的二维生长开辟了可能性。