Uniformity and Thickness Control of MoS2 During Thermolysis

Abstract

A solution-based thermolysis route for MoS2 synthesis was systematically investigated to identify the key process parameters for achieving scal-able and high-quality two-dimensional MoS2 with a uniform thickness. MoS2 was synthesized by spin coating a solution containing (NH4)2 MoS4 as the precursor. The crystallinity was found to be closely related to the process temperature, while the thickness exhibited a stronger dependence on the precursor solution concentration than the other process variables. However, controlling the thickness of MoS2 is strongly dependent on the solvent properties, such as viscosity. The thickness uniformity and surface coverage could be enhanced by adding ethanolamine to a mixture of N-dimethylformamide and n-butylamine, which hindered the formation of MoS42− clusters in the precursor and facilitated the synthesis of uniform thin films. With an appropriate solvent, the MoS2 thickness can be controlled more precisely by varying the precursor concentration.