Controllable synthesis of molybdenum tungsten disulfide alloy for vertically composition-controlled multilayer

摘要

The effective synthesis of two-dimensional transition metal dichalcogenides alloy is essential for successful application in electronic and optical devices based on a tunable band gap. Here we show a synthesis process for Mo_{1? x} W _x S₂ alloy using sulfurization of super-cycle atomic layer deposition Mo_{1? x} W _x O _y . Various spectroscopic and microscopic results indicate that the synthesized Mo_{1? x} W _x S₂ alloys have complete mixing of Mo and W atoms and tunable band gap by systematically controlled composition and layer number. Based on this, we synthesize a vertically composition-controlled (VCC) Mo_{1? x} W _x S₂ multilayer using five continuous super-cycles with different cycle ratios for each super-cycle. Angle-resolved X-ray photoemission spectroscopy, Raman and ultraviolet–visible spectrophotometer results reveal that a VCC Mo_{1? x} W _x S₂ multilayer has different vertical composition and broadband light absorption with strong interlayer coupling within a VCC Mo_{1? x} W _x S₂ multilayer. Further, we demonstrate that a VCC Mo_{1? x} W _x S₂ multilayer photodetector generates three to four times greater photocurrent than MoS₂- and WS₂-based devices, owing to the broadband light absorption.