Thermal vapor sulfurization of molybdenum layers

Highlights: • MoS₂ was synthesized by the thermal vapor sulfurization of pre-deposited molybdenum. • The quantity of molybdenum on SiO₂ can be easily controlled. • MoS₂ was homogeneous, high quality and continuous in the centimeter scale. -- Abstract: Sulfurization of molybdenum layers is a promising route for obtaining large-scale and high-quality transition metal dichalcogenides. Here we describe the synthesis of continuous and homogeneous MoS₂ in the centimeter scale by the thermal vapor sulfurization of pre-deposited molybdenum precursors on SiO₂. Metallic molybdenum as well as MoO₃ were used as precursors while the sulfurization was performed by chemical vapor deposition. A multi-technique characterization was employed to fully describe the deposition of molybdenum as well as its sulfurization. Thus, Raman spectroscopy, X-ray and ultra-violet photoelectron spectroscopies as well as scanning electron and atomic force microscopies indicated that the molybdenum layers were completely transformed in MoS₂. The samples were homogeneous in the centimeter scale and quite flat with a root mean square roughness of 1.4 Å. Furthermore, its work function was 4.1 eV.