設施農業：節能栽培與滅菌【材料科學與工程學系武東星教授】

論文篇名 英文：Characterization of aluminum gallium oxide films grown by pulsed laser deposition
中文：脈衝雷射沉積法製備氧化鋁鎵薄膜特徵
期刊名稱 Ceramics International
發表年份,卷數,起迄頁數 2018, , In Press
作者 Shuo-Huang Yuan, Sin-Liang Ou, Chien-Ming Chen(陳志銘), Shiau-Yuan Huang, Bo-Wen Hsiao, Dong Sing Wuu*(武東星)
DOI 10.1016/j.ceramint.2018.09.232
中文摘要 利用脈衝雷射沉積法(PLD)將氧化鋁鎵（AGO）膜沉積在c-平面藍寶石上。目前有關PLD製備AGO的研究中最常見的調變變數就是靶材成分與生長溫度，而其他的參數都設定為定值。這將會造成難以完整理解AGO膜的材料特性與相關理論。本研究中，許多生長相關參數像是靶材成分、氣體氛圍、雷射重複頻率、生長壓力與基板溫度都將作調變並用來了解AGO最佳化的生長條件。當使用鋁含量大於20%的氧化鋁鎵靶材時將會發生一個嚴重的靶材毒化現象並導致生長速率極度不穩定。與氬氣氛圍生長的AGO膜相比，氧氣氛圍製備的AGO膜傭有較高的透光度，這是因為膜內擁有大量的氧。在較高雷射重複頻率下製備的AGO膜因為同質的氧減少使得膜擁有較佳的結晶性。AGO膜內的鋁含量會隨著生長溫度增加而一同上升。使用較高的基板溫度會導致AGO膜傭有較寬的能隙、更加平滑的表面與減少的生長速率。此外，AGO膜的結晶品質可以透過提高長長壓力與基板溫度來改善。當在氧氣氛圍下利用(Al0.05Ga0.95)2O3靶材在固定工作壓力為2 × 10-1 torr、雷射重複頻率10 Hz與基板溫度800 °C將可以獲得較佳特徵的AGO膜。當金屬-半導體-金屬結構的光偵測器使用此AGO膜最為主動層時，將可以獲得最佳的特性如光電流7.56 ´ 10-8 A、暗電流1.59 ´ 10-12 A與光暗電流比4.76 ´ 104 (@5 V and 240 nm)。
英文摘要 Aluminum gallium oxide (AGO) films were prepared on conventional c-plane sapphire by pulsed laser deposition (PLD). In the current PLD-AGO studies, target composition or growth temperature is usually the main deposition variable, and the other growth conditions are fixed. This would make it difficult to fully understand the theory and characterization of AGO films. In this study, several growth parameters such as target composition, gas atmosphere, laser repetition frequency, growth pressure, and substrate temperature (Ts) were all modulated to realize and optimize the AGO growth. When the (AlxGa1-x)2O3 target with the Al content larger than 20 at.% was used, a serious target poisoning phenomenon occurred, leading to the extremely unstable growth rate. In comparison to the AGO film grown with argon atmosphere, the higher transparency was reached in the film prepared with oxygen atmosphere due to the relative abundance of oxygen. Because of the homogeneous oxygen reduction, the AGO film with the higher crystal quality was obtained at a higher laser repetition frequency. With an increment of growth pressure, the Al content of AGO film was increased. The growth of AGO film at the higher Ts would cause the higher bandgap value, smoother surface, and growth rate degradation. Additionally, the crystal quality of AGO film can be also improved both by increasing the growth pressure and Ts. The better characterization can be reached in the AGO film grown using the (Al0.05Ga0.95)2O3 target with oxygen atmosphere at the working pressure of 2 × 10−1 Torr, the laser repetition frequency of 10 Hz, and the Ts of 800 °C. When the metal-semiconductor-metal photodetector fabricated with this AGO active layer, the best performance including the photocurrent of 7.56 × 10−8 A, dark current of 1.59 × 10–12 A, and photo/dark current ratio of 4.76 × 104 (@5 V and 240 nm) were achieved.