Tailoring the surface properties of molybdenum oxytelluride thin films by its compositional ratio

Abstract

In this work, RF magnetron co-sputtering was used to fabricate molybdenum oxytelluride thin films with different atomic ratios. Scanning electron micrographs and atomic force micrographs revealed that pure Mo thin films were segregated. Thin films with 40% Te content portrayed needle-like structures and thus had the largest R_q value of 2.48 nm. Contact angle measurements further supported the findings as the thin films with 40% Te content were the most hydrophobic. X-ray photoelectron spectroscopy results revealed that the major oxidation states of Mo from Te-poor to Te-rich TFs were changed from high (+6) to low (+4 and/or +2). X-ray diffraction data showed that peaks pertaining to molybdenum oxide species appeared, notably at 33.048° and 33.115°. Ultraviolet photoelectron spectroscopy and Kelvin probe measurements evinced that the work function increases with increasing Te content. Four-point probe measurements revealed that molybdenum oxytelluride thin films tend to have higher electrical conductivity than pure Mo and Te thin films.