Molybdenum disulfide (MoS2), a graphene-like two-dimensional semiconductor with intriguing optical and electronic properties, has drawn increasing research interests. A single-layer MoS2 presents a sandwich structure where Mo atoms in the central place are hexagonally packed by two S atoms, whereas bulk MoS2 consists of multiple S–Mo–S stacking layers weakly bonded by Van de Waals forces. Bulk MoS2 was usually used as solid mechanical lubricating agent, while single-/few-layer MoS2 demonstrated prosperities for optical and electrical applications]. MoS2 has a thickness-dependent tunable band gap. Bulk MoS2 shows an indirect band gap of 1.2 eV, while monolayer MoS2 presents a direct band gap of 1.9 eV. The band gap could thus be designed as required by controlling the number of layers. MoS2 was also reported to have good carrier mobility of 517 cm2 V−1 s−1 in bulk state and 200 cm2 V−1 s−1 in monolayer state, which was favorable for the transportation of photo-generated electrons.