Alkali metal halides (AMHs) interaction with metal oxide precursors has been demonstrated to be an exciting and reliable method in the deposition of several atomically thin layered materials since the reaction rate is considerably enhanced. Using three different AMHs (KBr, NaCl, and KCl), we assisted the synthesis of MoSe₂ monolayers (MLs) in the atmospheric pressure chemical vapor deposition (APCVD) process in demonstrating that it is possible to improve the crystallinity of the MoSe₂ flakes and to induce the formation of 1T domains in the 2H MoSe₂ lattice that can be used to perform ultrahigh sensitive surface-enhanced Raman spectroscopy (SERS) detection. We observed that even though NaCl promotes the growth of large-sized MoSe₂ MLs, we found critical photoluminescence (PL) quenching originated from forming a Na-O layer underneath the MoSe₂ crystals. On the other hand, resonant Raman measurements show a prominent peak around 255 cm⁻¹ only in KBr-MoSe₂ single crystals originated from a double-resonant Raman process involving the ZA acoustic phonon and the C exciton, indicating optoelectronic-grade crystalline quality, thus explicating the higher PL emission in comparison with the other two AMH-assisted samples. KCl-MoSe₂ X-ray photoelectron spectroscopy (XPS) and Raman spectra display features matching the structural properties of 1T-MoSe₂ polyphase, confirming the existence of 1T domains embedded in the 2H-MoSe₂ lattice. Moreover, thermogravimetric analysis (TGA) measurements show that the KCl-MoO₂ mixture induces different sublimation processes compared with pure MoO_2, probably producing potassium-rich eutectic compounds that could stabilize the 1T-MoSe₂ domains. Finally, we demonstrate that the 1T-2H MoSe₂ monolayers synthesized at 750 °C showed a significant surface enhance Raman scattering activity towards the Rhodamine 6G and Methylene blue, with a detection limit comparable with plasmonic surfaces.

碱金属卤化物 (AMH) 与金属氧化物前体的相互作用已被证明是一种令人兴奋且可靠的方法，可用于沉积几种原子级薄层状材料，因为反应速率显着提高。使用三种不同的 AMH（KBr、NaCl 和 KCl），我们协助在常压化学气相沉积 (APCVD) 工艺中合成 MoSe ₂单层 (ML)，以证明可以提高 MoSe ₂薄片的结晶度并在 2H MoSe ₂晶格中诱导 1T 畴的形成，可用于进行超高灵敏度的表面增强拉曼光谱 (SERS) 检测。我们观察到即使 NaCl 促进了大尺寸 MoSe ₂MLs，我们发现临界光致发光 (PL) 猝灭源于在 MoSe ₂晶体下方形成 Na-O 层。另一方面，共振拉曼测量显示仅在 KBr-MoSe ₂单晶中的255 cm ^-1附近有一个突出的峰，该单晶源自涉及 ZA 声子和 C 激子的双共振拉曼过程，表明光电级晶体质量，因此解释了与其他两个 AMH 辅助样品相比更高的 PL 发射。KCl-MoSe ₂ X 射线光电子能谱 (XPS) 和拉曼光谱显示特征与 1T-MoSe ₂多相的结构特性相匹配，证实了 2H-MoSe _{2 中}嵌入的 1T 畴的存在格子。此外，热重分析 (TGA) 测量表明，与纯 MoO ₂相比，KCl-MoO ₂混合物引起不同的升华过程_，可能产生可以稳定 1T-MoSe ₂域的富钾共晶化合物。最后，我们证明了在 750 °C 合成的 1T-2H MoSe ₂单层对罗丹明 6G 和亚甲蓝显示出显着的表面增强拉曼散射活性，其检测限与等离子体表面相当。