Optical Spectroscopic Studies on Mono-Layer MoS2
Mono-layer Molybdenum Disulphide (MoS2) crystalline films were obtained on SiO2/Si substrate by mechanical exfoliation. The layer thickness was verified using Raman spectroscopy and Reflectance Contrast spectroscopy. Low temperature (4.5 K) micro-photoluminescence (μ-PL) measurements were performed on the MoS2 samples using a setup we have built which has a spatial resolution of <2 μm. The PL spectra shows two distinct features, one associated with the direct interband transition as the K point of the Brillouin zone of MoS2 and the other most likely associated with a defect. These results are compared with other reports of PL measurements on mono-layer MoS2 crystals.