Molybdenum disulfide (MoS2) has a graphene-like structure, which is a typical layered crystal, and consists of sulfur (S) and molybdenum (Mo) atoms, with individual layers bound to each other by van der Waals forces . MoS2 possesses excellent biocompatibility, strong visible light absorption, fluorescence quenching characteristics and a number of other interesting properties [6–8]. Due to these distinct electronic and physical/chemical properties, MoS2 has wide applications in many fields, such as opto-electronics, channel materials, biomedicine and dry lubrication [9–13]. Since ultrathin MoS2 shows much more attractive properties compared with bulk MoS2, large efforts have been made to develop methods for growing high quality ultrathin MoS2 films on various substrates. However, traditional top-down methods such as mechanical or chemical exfoliation are not suitable for the fabrication of large area, high-quality ultrathin MoS2 films [14–16]. Fortunately, MoS2 monolayers have been successfully grown on SiO2/Si substrates by chemical vapor deposition (CVD) . Moreover, pulsed laser deposition (PLD) also showed great potential for growing monolayer and thin multi-layer MoS2 films .