2D Materials: Molybdenum Disulfide for Electronic and Optoelectronic Devices

Abstract

Monolayer molybdenum disulfide (MoS2), a 2D semiconducting dichalcogenide material with a bandgap of 1.8–1.9 eV, has demonstrated promise for future use in field-effect transistors and optoelectronics. Various approaches have been used for MoS2 processing, the most common being chemical vapor deposition. During chemical vapor deposition, precursors such as Mo, MoO3, and MoCl5 have been used to form a vapor reaction with sulfur, resulting in thin films of MoS2. Currently, MoO3 ribbons and powder and MoCl5 powder have been used. In addition, sputtering of Mo produces continuous MoS2 films as well. Here we compare the structural properties of MoS2 grown by sulfurization of pulse vapor deposited MoO3 and Mo precursor films. Transmission electron microscopy and atomic force microscopy results demonstrate uniform and continuous film growth for the MoS2 films produced from Mo when compared to the films produced from MoO3. X-ray photoelectron spectroscopy results show that both precursors produce MoS2 films that were stoichiometric and had ~7–8 layers in thickness. We also found that, like other reports, infiltrating reduced graphene oxide during the sulfurization process increases MoS2 grain growth. Correlations between Mo and MoO3 layers and resulting 2D MoS2 film chemistry and structure are discussed.