稀磁性半導體之研究早期著重於氧化物摻雜 3d 過渡金屬進而誘發其鐵磁性，但近年來，有部份研究團隊於未摻雜之氧化物系統，亦發現其具有鐵磁性之行為，而究竟其磁性來源為何，則尚在研究當中；但目前部份研究團隊推測，應是由於材料本身的結構缺陷或是氧空缺所導致。
本實驗是利用離子束濺鍍(Ion Beam Sputter)薄膜儀來成長TiO2 薄膜樣品，目的乃是在於先成功成長出具室溫以上之鐵磁性的TiO2 薄膜後，再對其鐵磁性來源做更進一步地研究分析。首先，我們藉由TiO2 摻雜 Fe(20:0.5)，成功成長出具有室溫以上之鐵磁性的半導體薄膜；但此時卻也發現未摻雜之 TiO2 薄膜本身亦具有鐵磁行為，因此，接著我們針對未摻雜之 TiO2 薄膜做更進一步的研究，藉由成長時通入不同氧量與不同退火處理樣品，再經過X光繞射、片電阻量測與吸收光譜…等等的分析後，在確定其主體的長程與局部結構皆未有明顯變化的情況下，發現其鐵磁性與氧空缺的多寡有明顯的相對應之變化趨勢；證實氧缺陷確實是 TiO2 薄膜之磁性來源的主要因素之一。

In the study, we use the Ion Beam Sputter(IBS) to deposit TiO2 thin films, and try to understand the possible origin of room-temperature ferromagnetism(RTFM) in the TiO2 system. First, we successfully deposit the TiO2 films with RTFM by doping Fe in TiO2 films. But we also observe the RTFM behavior in the undoped TiO2 films. Therefore, we focus on the undoped TiO2 system. We deposit films under different oxygen flow conditions, and anneal the samples. And according to the analysis of the X-ray diffraction, sheet resistance, and absorption spectrum, the results suggest that the structure does not obviously vary. The ferromagnetism,however,changes with the concentration of oxygen vacancy. We conclude that the FM is correlated to the oxygen vacancy variation in the undoped TiO2 thin films system.

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