- 學位論文
鈷摻雜二硫化鉬的製備與量測
Preparation and characterization of cobalt-doped Molybdenum disulfide
摘要
本論文是由離子插層法剝離二硫化鉬塊材，剝離後的二硫化鉬混和氯化亞鈷水溶液產生沉澱，烘乾後得到鈷摻雜二硫化鉬樣品，對鈷摻雜二硫化鉬樣品進行結構量測。由拉曼光譜判斷剝離後的二硫化鉬之層數為兩層，E_2g^1與A_1g振動模式頻率產生變化是因為樣品合成後結構變化造成的。由X光繞射得到繞射圖譜，用布拉格公式(Bragg’s law)計算得到樣品之層間距，對照塊材層間距確定摻雜物有成功嵌入層間。在X光吸收光譜(XAFS)中，XANES圖與參考文獻圖類似，實驗過程中有產生氫氧根離子且容易與鈷離子結合，確定嵌入層間的為氫氧化鈷化合物，鈷K-edge的XANES隨著照X光時間的增加而改變；EXAFS發現隨著照X光時間增加鄰近鈷原子的配位數逐漸變小至消失。
並列摘要
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.