Lithium-Induced Reorientation of Few-Layer MoS Films.

Molybdenum disulfide (MoS) 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 MoS. However, the influence of lithium on the growth of MoS layers has not been fully explored. Here, we have studied how lithium affects the structural and optical properties of the MoS few-layer films prepared using a new method based on one-zone sulfurization with LiS as a source of lithium. This method enables incorporation of Li into octahedral and tetrahedral sites of the already prepared MoS films or during MoS 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 MoS films upon lithiation. The measurements show long-term stability and preserved chemical composition of the horizontally aligned Li-doped MoS.