Growth of 2-D MoS2 thin film by facile electrochemical deposition (original) (raw)

INTERNATIONAL CONFERENCE ON MULTIFUNCTIONAL MATERIALS (ICMM-2019)

Among all transition metal dichalcogenides (TMDs), MoS 2 shows very unique conducting and optoelectronic properties, which makes it the most suitable material for fabricating real-time sensors and atomically thin transistors. By chemical modifications, the MoS 2 can be made more useful in the field of various gas sensors, biosensors, and optoelectronic devices. In this study we present a novel facile method to grow 2-D MoS 2 thin films by electrochemical deposition technique. We have successfully grown MoS 2 thin films on ITO substrates through functionalization of MoS 2 nano-flakes in the presence of monochloroacetic acid (MCA). The functionalization of trigonal prismatic MoS 2 flakes with carboxyl group was achieved through sonication of MoS 2 solution in DI water in the presence of MCA and KOH. Due to weak van der Walls force between the sulphur-sulphur layers of MoS 2 flake, ultrasonic vibrations can easily intercalate the MoS 2 flakes, creating sulphur vacancies at the two outer side surfaces and further saturated by Cl atoms of the MCA, forming MoS 2-COOH composites. The as grown composites were then driven through linear sweep voltammetry on an ITO glass plate to form MoS 2 thin film by controlling the sweeping cycles. The growth of the thin film was confirmed by the cyclic voltammetric current responses, which show the corresponding change in oxidation peak currents after the deposition of MoS 2 thin film on the ITO substrates. It was further observed that the charge transfer decreases with the increase in thickness of the thin film as expected from the thick MoS 2 semiconductor. These 2-D MoS 2 can be of immense use in designing new type of real-time semiconducting biosensors, gas and electrochemical sensors, and atomically thin 2-D transistors.