本文利用離子束濺射系統成長Ga、Co共摻雜ZnO，並且利用快速熱退火（Rapid Thermal Annealing，RTA）後置處理，探討其磁性、電性及結構上之變化。實驗分為兩個部分，首先以Co摻雜ZnO薄膜和Co摻雜GZO(4wt%Ga2O3:96wt%ZnO)做比較，從結構上看來並沒有二次相(secondary phase)的產生，我們嘗試著做後置處理以釐清Ga元素置於ZnO:Co中所扮演影響著磁、電性的角色。而第二部分，則試著將Co摻雜GZO做低溫(250℃)並以不同條件下退火處理樣品，從Ga K-edge的XANES，我們發現Ga在退火前主要是以間隙位(interstitial)存在於樣品之中，而通氧退火的環境下則變成主要是取代位(substitutional) 。而似乎Ga的間隙位與磁性存在明顯的相依性，隨著退火時間拉長，無論是磁性或電性都產生有序的變化，所以，在此我們推斷此一磁性來源為間隙(interstitial) Ga的缺陷主導，我們將討論以束縛極化子模型(BMP model)或自由載子導致 (free carrier mediated) 磁性機制來解釋較為合理。

We study Ion Beam Sputter System (IBS) prepared (Ga,Co) co-doped ZnO and rapid thermal annealing (RTA) post-treated samples. We explore the magnetic, electrical and structural variations of these samples. The work was divided into two parts. First, we studied the structure of Co doped ZnO thin films and Co doped GZO (4wt% Ga2O3: 96wt% ZnO), no secondary phase was found.
Then we carried out post-annealing to understand the role of Ga element on the magnetic, electrical properties of (Co,Ga):ZnO. We annealed the Co doped GZO at 250℃under different conditions.From the Ga K-edge of XANES, we determined that Ga are mainly in interstitial sites before annealing and could effectively substitute Zn lattice sites in ZnO by annealing in oxygen environment. With increasing of the annealing time, both magnetic and electric properties changed in an order manner. The results suggest that this origin of the magnetism is closely related to the interstitial Gallium defects. We discussed the bound magnetic polaron model (BMP model) and free carrier mediated mechanism to account for the observed ferromagnetism.

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