以陽極氧化鋁模板製備氧化鋅奈米線及其發光性質之研究

Abstract

摘要 本實驗將利用高純度鋁(99.9%)經電化學之陽極處理法製作奈米孔洞結構之陽極氧化鋁模板(anodic aluminum oxide; AAO)。並利用直流電鍍法將低熔點的鋅(Zn)元素填入至陽極氧化鋁模板內，製得鋅金屬奈米線材。之後，將所製得之鋅奈米線材，經400℃、50小時的氧氣氣氛爐氧化後，獲得氧化鋅奈米線陣列，而後再以X-光繞射分析儀(XRD)、掃描式電子鏡(SEM)、原子力顯微鏡(AFM)和穿透式電子鏡(TEM)分析儀器觀察鋅奈米線和氧化鋅奈米線陣列的微觀結構及表面型態，其結果顯示出鋅原子藉由毛細現象(capillary effect)，讓氧化鋅奈米線能在氧化鋁管中得以成核和成長為wurtizite結構(繞射面方向(102)、(101))。而在光激發光能譜儀(photoluminescence ;PL)的分析中，氧化鋅奈米線的發光波長是取決於氧空孔，並且在15nm的氧化鋅奈米線中發現到，波長有藍位移的現象，顯示出在奈米尺寸的效應下，氣氛中的氧氣在高溫的環境下更容易進入到奈米線中，進而與氧空孔結合，使氧化的過程趨近於完全(2.76eV)。

In our experiment, specimens of high purity(99.999%) aluminum were used and fabricated nano-scale anodic alumina oxide (AAO),such as 200、60 and 15nm AAO by tow step anodic method .Using one step direct current electrodeposited low melting point of Zn to full up the anodic alumina oxide (AAO) and to fabricate Zn metal nanowire. Then, taking the fabricated nano-array Zn wire on AAO to get zinc oxide (ZnO) nano-wire array by oxide furnace at 400℃. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atom force microscopy (AFM) and X-ray Diffraction (XRD) were used to investigate the microstructure and surface morphology of the ZnO nanowires. The result indicate that zinc atom can nucleate and grow in high aspect ratio pore of AAO by capillary effect to form wurtitize structure((101)、(102)). It is found that photoluminescence (PL) spectrum of ZnO/AAO assembly system depends on the excitation wave, which is attributed to different types of oxygen vacancies in the ZnO nanowires. We observe when the diameter of ZnO was small at 15nm, the wavelength had a blue shift. We guess the oxygen can more easily into nanowire at high temperature oxidizing process and combine with oxygen vacancies to get perfect ZnO nanowires.