2D functional materials, such as 2D magnet and superconductor, spark massive interests from synthesis, manipulation to application. Especially, FeTe_x with multi-phases provides an ideal platform to explore the possible superconducting, ferromagnetic or antiferromagnetic properties and even their functional heterostructures. Herein, we report a facile chemical vapor deposition (CVD) approach to synthesize ultrathin tetragonal FeTe (down to monolayer), hexagonal FeTe (down to 2.3 nm), and Fe-rich hexagonal FeTe with superlattice by tuning the growth temperature according to the phase diagram. Scanning transmission electron microscopy (STEM) is further performed to confirm the difference among these various FeTe phases. Magneto-transport illustrates that the tetragonal device displays a high linear magnetoresistance (LMR) up to 10.5% at 1.9 K, and the LMR of hexagonal FeTe reaches 5.8% at 1.9 K. Interestingly, O doped tetragonal thick FeTe displays a superconducting transition at 9 K, which can persist even at 16 T. In summary, this study illustrates a phase-selective synthesis of FeTe_x ultrathin crystals, providing promising opportunities to construct complicated devices such as ferromagnet/antiferromagnet, magnet/superconductor heterostructures.

二维功能材料，如二维磁铁和超导体，从合成、操作到应用，都引起了广泛的兴趣。尤其是 FeTe _x多相提供了一个理想的平台来探索可能的超导、铁磁或反铁磁特性，甚至它们的功能异质结构。在此，我们报告了一种简便的化学气相沉积 (CVD) 方法，通过根据相调整生长温度来合成超薄四方 FeTe（低至单层）、六方 FeTe（低至 2.3 nm）和具有超晶格的富 Fe 六方 FeTe图表。进一步执行扫描透射电子显微镜 (STEM) 以确认这些不同 FeTe 相之间的差异。磁传输说明四方器件在 1.9 K 时显示出高达 10.5% 的高线性磁阻 (LMR)，六方 FeTe 的 LMR 在 1.9 K 时达到 5.8%。有趣的是，O 掺杂的四方厚 FeTe 在 9 时显示出超导跃迁克，_x超薄晶体，为构建复杂器件（如铁磁体/反铁磁体、磁体/超导体异质结构）提供了有希望的机会。