Synthesis of Ultrathin FeS Nanosheets via Chemical Vapor Deposition

Abstract Fe‐based 2D materials exhibit rich chemical compositions and structures, which may imply many unique physical properties and promising applications. However, achieving controllable preparation of ultrathin non‐layered FeS crystal on SiO 2 /Si substrate remains a challenge. Herein, the influence of temperature and molecular sieves is reported on the synthesis of ultrathin FeS nanosheets with a thickness as low as 2.3 nm by molecular sieves‐assisted chemical vapor deposition (CVD). The grown FeS nanosheets exhibit a non‐layered hexagonal NiAs structure and belong to the P6 3 /mmc space group. The inverted symmetry broken structure is confirmed by the angle‐resolved second harmonic generation (SHG) test. In particular, the 2D FeS nanosheets exhibit exceptional metallic behavior, with conductivity up to 1.63 × 10 6 S m −1 at 300 K for an 8 nm thick sample, which is higher than that of reported 2D metallic materials. This work provides a significant contribution to the synthesis and characterization of 2D non‐layered Fe‐based materials.