HIGHLY LUMINISCENT MoS2 NANOSHEETS OBTAINED VIA TOP-DOWN APPROACH

Abstract

Here, we report the synthesis of hetero-dimensional nanosheets of MoS2 via a facile probe-sonication method. Structural analysis using X-ray diffraction revealed the hexagonal phase of synthesized MoS2nanosheets. Transmission electron microscopy images indicated the presence of (004) planes and hexagonal symmetry of the processed nanosheets. These results were further supported by Raman spectra, which clearly revealed the reduction in intensity ratio of A1g and E12g modes of MoS2. Whereas, MoS2 in bulk form is an indirect bandgap material and no emission is expected, the scaled MoS2nanosheets have shown significant photoluminescence emission in the wavelength range from 300 to 550 nm. These results suggest that an indirect to direct bandgap transformation in MoS2 with reduction in no of layers give rise to enhancement in the photoluminescence emission. This way one can optimize the emission in desired range of the spectrum.