Synthesis of large-scale 2-D MoS2 atomic layers by hydrogen-free and promoter-free chemical vapor deposition

As one of the two-dimensional (2-D) transition metal dichalcogenides, atomically thin molybdenum disulfide (MoS2) has attracted significant attention and research interests for micro and nanoelectronic applications. Significant efforts have been made to develop different approaches in order to obtain atomic layer MoS2, such as exfoliation, chemical synthesis, and physical or chemical vapor deposition (CVD) processes. In this paper, we report a hydrogen-free and promoter-free CVD growth to synthesize large-area MoS2 atomic layers. A variety of techniques including optical microscopy (OM), atomic force microscopy (AFM), photoluminescence (PL) mapping, Raman and x-ray photoelectron spectroscopy (XPS), high resolution electron microscopy (HREM) and scanning transmission electron microscopy (STEM) were applied to characterize the film quality, uniformity and layer numbers. High quality centimeter-sized MoS2 atomic layers were demonstrated, which form a foundation to develop wafer-sized material platform for device fabrication and production.