Pressure-dependent large area synthesis and electronic structure of MoS2

Abstract Molybdenum disulfide (MoS 2 ) is a transition metal dichalcogenide, which along with graphene, has a great potential to become a material of choice for the next generation of nanoelectronics. We report the synthesis of a large-area MoS 2 obtained by sulfurization of MoO 3 using chemical vapor deposition (CVD) at different Ar base pressures. The optimal pressure for the growth was found to be ∼50 mbar (millibar). The evolution of MoS 2 phase as a function of Ar gas pressure was monitored by confocal Raman spectroscopy. As synthesized MoS 2 shows direct bandgap of 1.6 eV evaluated by UV–vis spectroscopy. We report for the first time the valence band spectra and the work function of MoS 2 on SiO 2 /Si calculated by ultraviolet photoemission spectroscopy, which was found to be 4.67 eV. In-situ electrical measurements demonstrated expected semiconducting behavior of the grown triangular crystals. These studies show MoS 2 crystallites growth by controlling the parameters in CVD process.