Synthesis of uniform two-dimensional MoS₂ films via thermal evaporation

Two-dimensional (2D) molybdenum disulfide (MoS₂) 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 MoS₂ due to its high melting temperature of 1375 °C. As a result, only thick and rough MoS₂ 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 MoS₂ thin films. By using K₂MoS₄ as the precursor, we achieved reliable deposition of uniform polycrystalline MoS₂ 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 MoS₂ using shadow masks and sequential deposition of MoS₂ and tungsten disulfide (WS₂), similar to conventional thermal evaporation techniques. Moreover, we have demonstrated the potential applications of the obtained MoS₂ thin films in field effect transistors (FETs), memristors and electrocatalysts for hydrogen evolution reaction (HER).