水溶液法製備氧化鋅薄膜及其光學特性研究

Preparation and Optical Properties of ZnO Thin Films from Aqueous Solutions

莊佑豪(Yo-hao Chuang)

指導教授 ： 林永仁

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

本研究主要是以水溶液法成長氧化鋅，利用旋轉塗佈法於玻璃基板上製備一低溫乾燥之晶種層，再將此晶種層於水溶液中成長氧化鋅，第一部份是改變溶液中硝酸鋅/HMTA(環六甬基胺)的莫耳比、硝酸鋅初始濃度及成長時間，探討各變數對氧化鋅成長的影響。第二部份是利用甪口實驗法，並於水溶液中添加氯化鋁作為鋁離子來源，利用望目特性以透光率為85%，找出氧化鋅薄膜成長之最佳參數組合。
在實驗中，利用水溶液法於硝酸鋅初始濃度為0.04M，80°C持溫一小時；甫XRD的結果可知在莫耳比為2時有最高的結晶性，且莫耳比大於2時，結晶性隨莫耳比增加而下降；在透光率分析的結果可知，莫耳比為2至14時透光率隨莫耳比增加而增加，在莫耳比14時，於可見光區(400~700nm)帄均透光率可達94%，在莫耳比為17時透光率則減低至87%；利用SEM觀察表面形態可知，莫耳比低於14時氧化鋅以柱狀成長為主，而莫耳比為17時，則出現柱狀及片狀複合成長之氧化鋅；甫螢光光譜儀的結果中可知，莫耳比1時，氧化鋅成長時不易形成鋅原子格隙缺陷，可成長高品質的氧化鋅，當莫耳比增加時，鋅原子格隙缺陷增加，造成鋅原子格隙缺陷螢光發光(photon energy=2.9eV)強度增加。
在甪口方法方面，利用透光率作為品質特性，以望目85%的透光
VII
率作為目標，經分析後得到成長透光率85%的氧化鋅薄膜，最佳成長條件為，硝酸鋅/HMTA莫耳比9，硝酸鋅初始濃度0.01M，鋁原子百分比0.2%，於60°C成長1小時。在85%透光率的最佳條件下成長的薄膜，氧化鋅主要以片狀成長，透光率為91.1%，與目標之85%透光率為誤差百分比為7.14%。

關鍵字

氧化鋅 ； 薄膜 ； 水溶液法 ； 田口方法 ； 溶膠凝膠 ； 低溫製程

並列摘要

Zinc oxide film was grown in aqueous solutions. Glass substrates were first spin-coated with a seed layer of dried ZnO gel. Then, they were deposited of ZnO in aqueous solutions. The effects of Zinc nitrate/HMTA(hexamethylenetetramine) molar ratio, Zinc nitrate concentration and deposition time on the growth of ZnO were studied. The other part of the thesis was to find optimal processing conditions using Taguchi method for fabrication of AZO thin film with 85% of transmittance in visible light range.
XRD results showed that, in an aqueous solution with initial Zinc nitrate concentration 0.04M, deposited 1 hour at 80°C, when molar ratio of Zinc nitrate/HMTA was 2, we obtained ZnO film with highest crystallinity. The crystallinity decreased as the molar ratio increased. Visible light transmittance increased, when the molar ratio increased from 2 to 14. Highest transmittance was 94% when the ratio was 14. Under such condition ZnO grew as rods. However, ZnO grew in rod/plate complex morphology when the molar ratio was 17. From photoluminescence results, when zinc nitrate/HMTA ratio was 1, we could obtain the ZnO crystal with low Zn atom interstitial defect.
In Taguchi method we set the goal as 85% transmittance in visible light range. The optimal conditions was derived as: zinc nitrate initial concentration was 0.01M, zinc nitrate/HMTA ratio was 9, deposited in 60°C for 1hour with 0.2at% Al. ZnO film grown

並列關鍵字

sol-gel ； ZnO ； thin film ； aqueous solution ； Taguchi method ； low-temperature process

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