Lithium-Induced Reorientation of Few-Layer MoS₂ Films

Molybdenum disulfide (MoS₂) few-layer films have gained considerable attention for their possible applications in electronics and optics and also as a promising material for energy conversion and storage. Intercalating alkali metals, such as lithium, offers the opportunity to engineer the electronic properties of MoS₂. However, the influence of lithium on the growth of MoS₂ layers has not been fully explored. Here, we have studied how lithium affects the structural and optical properties of the MoS₂ few-layer films prepared using a new method based on one-zone sulfurization with Li₂S as a source of lithium. This method enables incorporation of Li into octahedral and tetrahedral sites of the already prepared MoS₂ films or during MoS₂ formation. Our results discover an important effect of lithium promoting the epitaxial growth and horizontal alignment of the films. Moreover, we have observed a vertical-to-horizontal reorientation in vertically aligned MoS₂ films upon lithiation. The measurements show long-term stability and preserved chemical composition of the horizontally aligned Li-doped MoS₂.