Silver Nanoparticles Decorated Wide Band Gap MoS2 Nanosheet: Enhanced Optical and Electrical Properties

Metal nanoparticles decorated molybdenum disulfide (MoS2) nanosheets have received great attention of researchers due to their potential applications in biosensing, optoelectronics, photocatalysis, SERS, etc. Here, we report the enhanced optical and electrical properties of wide band gap MoS2 nanosheets decorated with silver nanoparticles (Ag-MoS2 nanosheets). Field emission scanning electron spectroscopy (FESEM) images reveal the formation of well-shaped MoS2 nanosheet-like structures decorated with silver nanowires. MoS2 nanosheets are 27.9 mu m long and 12.9 mu m wide and the thickness is in the range of nanometer. X-ray diffraction (XRD) spectra show peaks at 33.79 degrees, 36.28 degrees, 50.97 degrees, and 72.04 degrees corresponding to (100), (102), (105), and (203) crystalline planes for pure MoS2 and at 38.8 degrees, 47.26 degrees, and 78.28 degrees corresponding to the (111), (200), and (311) crystalline planes for silver in Ag-MoS2 nanosheets, respectively. The UV-Vis absorption peak is observed at 340 nm for MoS2 but gets blue-shifted for Ag-MoS2 nanosheets. The calculated band gap is found to be 3.05 eV for MoS2 nanosheet, so it falls under the category of wide band gap (2-4 eV) semiconductors which can have potential application in UV photodetection. From the photoluminescence spectra, we have observed enhanced emission for Ag-MoS2 in the range of 410-470 nm for the excitation wavelength 280 nm. Raman peak intensity of MoS2 nanosheets has increased significantly when decorated with Ag nanostructure which can have potential SERS application. I-V characteristic of Ag-MoS2 nanosheets under illumination exhibits negative photoconductivity but is positive for pristine MoS2 nanosheets.