Abstract
In this thesis, we studied the structures and physical properties of cobalt-doped Molybdenum disulfide. To prepare the Co-doped MoS2 samples, the Molybdenum disulfide bulk was stripped by ion intercalation. The stripped Molybdenum disulfide was mixed with aqueous cobalt chloride solution to form precipitates. After drying in an oven, cobalt-doped Molybdenum disulfide samples were obtained. A variety of experimental methods such us Raman spectroscopy, x-ray diffraction (XRD), x-ray absorption fine structures (XAFS) have been used to investigate the structures. The number of layers of the Molybdenum disulfide after stripping was determined by Raman spectroscopy to be two layers. The frequency of E_2g^1 and A_1g vibration modes are changed, because of structural changes after sample synthesis. The X-ray diffraction (XRD) patterns were obtained by using synchrotron x-ray sources. The interlayer spacing of the sample obtained from XRD analysis using Bragg's law appeared to be larger compared to that of the bulk. We conclude that the dopant atoms were successfully intercalated in the interlayer. The XANES spectra of the samples are similar to the reference spectrum. We have also found that hydroxide ions, which can be easily bonded to cobalt ions, were generated during the experiments. The intercalated layer appears to be a cobalt hydroxide compound. The cobalt K-edge XANES spectra changed with time as the sample is continually irradiated by x-rays. The EXAFS data also show a peculiar variation of coordination numbers of the neighboring shells surrounding the cobalt atoms as the samples are being irradiated by x-rays.