本研究中我們使用固態反應法和化學沉積法兩種方法製作鈷摻雜量在0.5％-16%間的摻鈷氧化鋅粉末。粉末X光繞射圖顯示大部分晶格繞峰位置會隨著鈷的濃度增加，而移至較低角度；此結果顯示摻鈷氧化鋅的晶格常數隨著鈷含量增加而變大。拉曼光譜圖顯示摻鈷氧化鋅的其中三個聲子震動模組A1、E1、E2，隨著鈷含量增加而移到較低的頻率。此外，A1聲子震動模組的強度隨著鈷含量而增加，表示鈷氧間的電子極化強度比鋅氧間的還強。超導量子干涉磁化儀的測量結果，顯示摻鈷氧化鋅在室溫時呈現順磁性。以化學沉積法製備得的摻鈷氧化鋅粉末比使用固態反應法所得的粉末具有較強的磁化強度。化學沉積法所製備的16%摻鈷氧化鋅樣品有高達0.130 emu/g•T的磁化率。X光吸收光譜圖顯示摻鈷氧化鋅結構中的鈷是屬於+2氧化數。

In this study, we report high cobalt concentration doped ZnO (Co content from 0 up to 16%) prepared by both solid reaction and chemical precipitation methods. The X-ray powder diffraction patterns show that most diffraction peaks slightly shift to lower degrees with increasing cobalt content. As a result, the crystal lattice constant increases with the Co content. Our results of Raman scattering spectra show that the A1, E1 and E2 vibration phonon modes of Co-ZnO shift to lower frequencies with increasing cobalt concentration. The intensity of the A1 mode increase with the Co content. The electric polarization of Co-O is stronger than that of Zn-O. The results of SQUID magnetometer show that the Co-ZnO samples fabricated by the chemical precipitation method exhibit paramagnetic property with magnetic susceptibility up to 0.1296 emu/g•T at 16% Co content under room temperature. The Co-ZnO samples prepared by chemical precipitation method have stronger paramagnetic property than samples by solid reaction. The result of X-ray absorption near edge structure shows the Co atoms in Co-ZnO structure are at +2 oxidation state.

中文摘要 I
Abstract II
Acknowledge III
List of Figures IV
List of Table V
Table of contents 1
1. Introduction 2
1.1 Dilute Magnetic Semiconductors 2
1.2 Zener Model 4
1.3 Zinc Oxide 6
2. Experimental Details 9
2.1 Sample Preparation 9
2.2 Crystal Structure Measurement 12
2.3 Phonon Mode Measurement-Raman Scattering Spectra 14
2.4 Room Temperature Magnetization vs Magnetic Field 17
3. Results & Discussion 19
3.1 Crystal Structure 19
3.2 Phonon Modes of Lattice Vibration 29
3.3 Magnetic Properties 37
3.4 X-Ray Absorption Near Edge Structure (XANES) 41
4. Conclusion 43
5. References 44

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