Synthesis of uniform two-dimensional MoS2 films via thermal evaporation

Abstract

Two-dimensional (2D) molybdenum disulfide (MoS 2 ) holds great potential for various applications such as electronic devices, catalysis, lubrication, anti-corrosion and so on. Thermal evaporation is a versatile thin film deposition technique, however, the conventional thermal evaporation techniques face challenges in producing uniform thin films of MoS 2 due to its high melting temperature of 1375 °C. As a result, only thick and rough MoS 2 films can be obtained using these methods. To address this issue, we have designed a vacuum thermal evaporation system specifically for large-scale preparation of MoS 2 thin films. By using K 2 MoS 4 as the precursor, we achieved reliable deposition of uniform polycrystalline MoS 2 thin films with a size of 50 mm × 50 mm and controllable thickness ranging from 0.8 to 2.4 nm. This approach also allows for patterned deposition of MoS 2 using shadow masks and sequential deposition of MoS 2 and tungsten disulfide (WS 2 ), similar to conventional thermal evaporation techniques. Moreover, we have demonstrated the potential applications of the obtained MoS 2 thin films in field effect transistors (FETs), memristors and electrocatalysts for hydrogen evolution reaction (HER).