Direct Formation of 2-dimensional Molybdenum Disulfide Thin Films by RF Sputtering and Rapid Thermal Annealing on Sapphire Substrate

Abstract

For the realization of well-patterned two-dimensional transition metal dichalcogenide (TMDC) films, molybdenum disulfide (MoS2) films were formed on sapphire substrate by radio-frequency (RF) sputtering with a shadow mask followed by rapid thermal annealing (RTA). The films were deposited using various sputtering power and annealed at different temperatures of 600 to 800 degrees C. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) indicate more noticeable peaks when higher RF power and annealing temperature are used. However, analyses with a scanning electron microscope (SEM) and atomic force microscope (AFM) show that the MoS2 films sputtered at lower RF sputtering power have a better surface as a result of the different coefficients of thermal expansion (CTEs). The high mobility and carrier density were also investigated for all the MoS2 films.