Synthesis of Mo1-xWxS2 by Atomic Layer Deposition for Atomically Thin Gas Sensor

Abstract

Two-dimensional Transition metal dichalcogenide (2D TMDC) have been attracted great attention as gas sensing materials with high sensitivity in room temperature. [1] Because of this characteristic, 2D TMDC gas sensor could overcome the oxide-based semiconductor which need heating for gas sensing. Therefore, various 2D TMDC gas sensor studies have been ongoing. Recently, it has been shown that the gas sensor property could be improved through the changing the composition in WS2xSe2-2x alloy. [2] Here we report a synthesis method of Mo1-xWxS2 alloys for gas sensor by atomic layer deposition. Layer controlled 2D MoS2 and WS2 were synthesized with Mo(CO)6, W(CO) 6 and H2S as precursors and reactant. We systematically modulate the composition of Mo1-xWxS2 alloys by changing the configuration of ALD super-cycles. AFM and Raman spectroscopy results of Mo1-xWxS2 alloys demonstrate the composition change of alloy. Furthermore, gas sensors fabricated by Mo1-xWxS2 alloys were evaluated for NO2 gas. It showed response time shortened in alloy.