- 學位論文
摻雜鉻之二硒化鉬(Mo1-xCrxSe2, x=0, 0.5)磁、電結構研究
Studies of magnetic and electric properties MoSe2 Cr doped
摘要
本論文以水熱法製成MoSe2 及Mo0.5Cr0.5Se2 二維結構的材料。因 此X 光繞射(XDR, X-Ray Diffraction )之結果具不對稱之繞射峰。因此 須使用第白散射方程式( Debye scattering equation )去模擬出XRD 圖， 藉由模型得到近似的結構組成參數。並且與HR-TEM 去觀測MoSe2 及Mo0.5Cr0.5Se2 之表面形貌的結果相互比較，並確認晶體的成相為1T 結構佔60%。 變溫拉曼實驗顯示了MoSe2 與Mo0.5Cr0.5Se2 於130 至180 K 以及 200 至230 K 這兩處溫區展現了峰值強度與寬度的改變。但外加 200mT 的磁場便可以使該扭曲消失。這顯示了此一扭曲可以被外加磁 場抑制。暗示了兩種樣品的此一扭曲與磁有著交互作用。 比對變溫拉曼峰之半高寬與變溫XRD 峰值位置的趨勢變化，發 現了兩者呈現反對稱的變化。而在變電場PL 實驗中也發現了隨著變 場改變PL 光譜的趨勢也與變電場拉曼所得的趨勢圖有著相仿的結果。 因此可以知電場使得結構產生了扭曲，並進一步影響到能隙之大小。
並列摘要
Using hydrothermal method to fabricate the materials MoSe2 and Mo0.5Cr0.5Se2. The result of X-Ray Diffraction shows asymmetric diffraction peak. For the reason that XRD pattern have to use Debye scattering equation to simulate and get model of the structure to compose parameters. To compare with the surface countenance of MoSe2 and Mo0.5Cr0.5Se2 by using HR-TEM. To Confirm that 1T structure account for 60 percent of all the phase. Variable temperature Raman experiments reveal that MoSe2 and Mo0.5Cr0.5Se2 change in both the width and the peak intensity , At 130 to 180 K and 200 to 230K these two temperature zones. With additional 200mT magnetic field can get rid of the distortion. Thence, the distortion can be curbed by additional magnetic field. This implies that the distortion and the magnetic field of two samples have interaction between them. Compares with the trends of the variable temperature Raman peaks FWHM and variable temperature XRD peak position. There exhibit an antisymmetric change. In varying electric PL experiments found the similar trends with the alternating electric field Raman that can be aware of structure generating distortion by electric field also can be further affect the size of the energy gap.