Synthesis and characterization of MoS₂ nanosheets

Here, we report on the synthesis of MoS₂ nanosheets using a simple two-step additive-free growth technique. The as-synthesized nanosheets were characterized to determine their structure and composition, as well as their optical properties. The MoS₂ nanosheets were analyzed by scanning electron microscopy, transmission electron microscopy (TEM), including high-resolution scanning TEM imaging and energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and photoluminescence (PL). The as-produced MoS₂ nanosheets are vertically aligned with curved edges and are densely populated. The TEM measurements confirmed that the nanosheets have the 2H-MoS₂ crystal structure in agreement with the Raman results. The XPS results revealed the presence of high purity MoS₂. Moreover, a prominent PL similar to mechanically exfoliated few and mono-layer MoS₂ was observed for the as-grown nanosheets. For the thin (≤50 nm) nanosheets, the PL feature was observed at the same energy as that for a direct band-gap monolayer MoS₂ (1.83 eV). Thus, the as-produced high-quality, large-area, MoS₂ nanosheets could be potentially useful for various optoelectronic and catalysis applications.