利用低溫水熱法製備氧化鋅奈米柱

Fabrication of ZnO Nanorod Using Hydaro-Thermal Method at Low Temperature

葉輔湘(Fu-Hsiang Yeh)

指導教授 ： 謝淑惠

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2010年)

https://doi.org/10.6827/NFU.2010.00089

摘要

本文主要是以水熱法生長奈米氧化鋅，選用3種不同基板測試(具有ZnO晶種層之Si基板、Si基板、Cu基板)，實際結果發現使用ZnO晶種之Si層基板生長之氧化鋅柱較規則排列，因此選用已長ZnO晶種層之Si基板(ZnO/Si)生長奈米氧化鋅。第一部分是探討經由氨水添加改變溶液中的pH值、反應溫度、成長時間等變數對氧化鋅柱成長及性質變化的影響。第二部分是探討氧化鋅柱晶體不同晶面的成長速率，利用爐冷時效產生逆反應形成氧化鋅柱的中空結構。
實驗中，利用水熱法於水溶液條件為氯化鋅濃度設定在0.1 M，pH值10.0，95℃持溫1.5小時後，可順利在ZnO/Si基板表面沈積氧化鋅奈米柱直徑為50~70 nm；由XRD分析結果可知氧化鋅奈米柱是六角形纖維鋅礦結構 (Wurtzite structure)，屬於六方晶系，其中（0002）面特徵峰最強，再經由TEM擇區繞射圖判別此方法生成的氧化鋅柱為單晶六角形氧化鋅奈米柱，朝[0001]方向生長。實驗結果發現反應溫度高於70℃時即可發生氧化鋅生成反應，實驗過程選用不同pH值從8.5至11.0的反應溶液，而pH值為8.5至10.0時生成的氧化鋅為奈米線，而pH10.0至10.5時生成氧化鋅奈米柱，當pH值上升氧化鋅柱面隨之粗化，至pH10.5時氧化鋅為微米柱。由螢光光譜儀的結果中可知，pH值為9.0時有相對高強度的氧化鋅本質發光能帶紫外光放射，但隨著pH值的提高氧化鋅柱面而隨之粗化而綠光放射亦變強，此結果推論係氧化鋅表面氧空位缺陷導致綠光放射變強，使得氧化鋅本質發光能帶隨之下降，因此隨著pH值的提高，生成直徑較大的六角形氧化鋅柱，而此微米氧化鋅柱成長過程係快速往c軸方向生長，所以導致缺陷增多影響了氧化鋅的晶體品質。同時由於六角柱頂面氧空缺，使得富鋅(0001)極性面處於亞穩狀態，透過時效處理可溶解直徑大於250 nm的氧化鋅柱，形成微米氧化鋅管。

關鍵字

氧化鋅 ； 奈米柱

並列摘要

In this study, the simple hydrothermal method was used to fabricate nano ZnO on different substrates including Si plate, Cu plate and Si plate which had been deposited a ZnO seed layer (ZnO/Si plate) on. The preliminary experiment result showed ZnO nanorods were in order on ZnO /Si plate. And then, ZnO/Si plates were used as the substrates to deposit ZnO, the dependence of the morphologies and properties of ZnO on the solution pH value, the growth temperature and time were investigated in detail. Finally, the experiments were carried out to observe the mechanism of tubular ZnO formation.
The experimental results showed that the ZnO nanorods of diameter 50~70 nm were grown on ZnO/Si substrates at the condition of ZnCl2 solution 0.1 M, hydrothermal solution pH 10.0 and 95℃. The TEM, XRD and TEM diffraction pattern observation revealed the ZnO nanorods are single crystals with HCP structure and have the preferred orientation [0001]. The hydrothermal decomposition method would start to grow ZnO at growth temperature above 70℃. ZnO nanowires and nanorods were grown on the ZnO/Si plate at the pH range of 8.5-10.0 and 10.0-10.5, separately. The fluorescence spectroscopy analysis showed that ZnO nanorods grown at bath pH 9.0 had a relatively strong intrinsic light emission at the UV band. Increasing hydrothermal bath pH, the grown ZnO rods had a relatively weak intrinsic light emission at the UV band and a strong green emission which indicates the HCP structure of ZnO rods much dominated at the C axis and formed surface oxygen vacancies.
The tubular ZnO would originate from ageing process from ZnO rods of diameter larger than 250 nm due to the preferential dissolution of the metastable Zn-rich (0001) polar surfaces.

並列關鍵字

ZnO Nanorod ； Hydaro-Thermal Method

參考文獻

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